machine screws and nuts - Sport Pilot Information Page

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Machinery's Handbook 27th Edition
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MACHINE SCREWS
1587
MACHINE SCREWS AND NUTS
American National Standard Machine Screws and Machine Screw Nuts.—T h i s
Standard ANSI B18.6.3 covers both slotted and recessed head machine screws. Dimensions of various types of slotted machine screws, machine screw nuts, and header points
are given in Tables 1 through 12. The Standard also covers flat trim head, oval trim head
and drilled fillister head machine screws and gives cross recess dimensions and gaging
dimensions for all types of machine screw heads. Information on metric machine screws
B18.6.7M is given beginning on page 1596.
Threads: Except for sizes 0000, 000, and 00, machine screw threads may be either Unified Coarse (UNC) and Fine thread (UNF) Class 2A (see American Standard for Unified
Screw Threads starting on page 1732) or UNRC and UNRF Series, at option of manufacturer. Thread dimensions for sizes 0000, 000, and 00 are given in Table 7 on page 1592.
Threads for hexagon machine screw nuts may be either UNC or UNF, Class 2B, and for
square machine screw nuts are UNC Class 2B.
Length of thread: Machine screws of sizes No. 5 and smaller with nominal lengths equal
to 3 diameters and shorter have full form threads extending to within 1 pitch (thread) of the
bearing surface of the head, or closer, if practicable. Nominal lengths greater than 3 diameters, up to and including 11⁄8 inch, have full form threads extending to within two pitches
(threads) of the bearing surface of the head, or closer, if practicable. Unless otherwise specified, screws of longer nominal length have a minimum length of full form thread of 1.00
inch.Machine screws of sizes No. 6 and larger with nominal length equal to 3 diameters
and shorter have full form threads extending to within 1 pitch (thread) of the bearing surface of the head, or closer, if practicable. Nominal lengths greater than 3 diameters, up to
and including 2 inches, have full form threads extending to within 2 pitches (threads) of the
bearing surface of the head, or closer, if practicable. Screws of longer nominal length,
unless otherwise specified, have a minimum length of full form thread of 1.50 inches.
Table 1. Square and Hexagon Machine Screw Nuts ANSI B18.6.3-1972 (R1991)
F
H
F
H
Optional;
See Note
G1
G
30
30
Nom.
Size
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
Basic
Dia.
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.3125
0.3750
Basic
F
5⁄
32
5⁄
32
3⁄
16
3⁄
16
1⁄
4
5⁄
16
5⁄
16
11⁄
32
3⁄
8
7⁄
16
7⁄
16
9⁄
16
5⁄
8
Max.
F
0.156
0.156
0.188
0.188
0.250
0.312
0.312
0.344
0.375
0.438
0.438
0.562
0.625
Min.
F
0.150
0.150
0.180
0.180
0.241
0.302
0.302
0.332
0.362
0.423
0.423
0.545
0.607
Max.
G
0.221
0.221
0.265
0.265
0.354
0.442
0.442
0.486
0.530
0.619
0.619
0.795
0.884
Min.
G
0.206
0.206
0.247
0.247
0.331
0.415
0.415
0.456
0.497
0.581
0.581
0.748
0.833
Max.
G1
Min.
G1
0.180
0.180
0.217
0.217
0.289
0.361
0.361
0.397
0.433
0.505
0.505
0.650
0.722
0.171
0.171
0.205
0.205
0.275
0.344
0.344
0.378
0.413
0.482
0.482
0.621
0.692
Max.
H
0.050
0.050
0.066
0.066
0.098
0.114
0.114
0.130
0.130
0.161
0.193
0.225
0.257
Min.
H
0.043
0.043
0.057
0.057
0.087
0.102
0.102
0.117
0.117
0.148
0.178
0.208
0.239
All dimensions in inches. Hexagon machine screw nuts have tops flat and chamfered. Diameter of
top circle should be the maximum width across flats within a tolerance of minus 15 per cent. Bottoms
are flat but may be chamfered if so specified. Square machine screw nuts have tops and bottoms flat
without chamfer.
Copyright 2004, Industrial Press, Inc., New York, NY
1588
MACHINE SCREWS
Diameter of body: The diameter of machine screw bodies is not less than Class 2A thread
minimum pitch diameter nor greater than the basic major diameter of the thread. Crossrecessed trim head machine screws not threaded to the head have an 0.062 in. minimum
length shoulder under the head with diameter limits as specified in the dimensional tables
in the standard.
Designation: Machine screws are designated by the following data in the sequence
shown: Nominal size (number, fraction, or decimal equivalent); threads per inch; nominal
length (fraction or decimal equivalent); product name, including head type and driving
provision; header point, if desired; material; and protective finish, if required. For example:
1⁄ − 20 × 11⁄ Slotted Pan Head Machine Screw, Steel, Zinc Plated
4
4
6 − 32 × 3⁄4 Type IA Cross Recessed Fillister Head Machine Screw, Brass
Machine screw nuts are designated by the following data in the sequence shown: Nominal size (number, fraction, or decimal equivalent); threads per inch; product name; material; and protective finish, if required. For example:
10 − 24 Hexagon Machine Screw Nut, Steel, Zinc Plated
0.138 − 32 Square Machine Screw Nut, Brass
Table 2. American National Standard Slotted 100-Degree Flat Countersunk
Head Machine Screws ANSI B18.6.3-1972 (R1977)
T
J
99
101
A
H
L
Nominal
Sizea
or Basic
Screw Dia.
0000
000
00
0
1
2
3
4
6
8
10
1⁄
4
5⁄
16
3⁄
8
0.0210
0.0340
0.0470
0.0600
0.0730
0.0860
0.0990
0.1120
0.1380
0.1640
0.1900
0.2500
0.3125
0.3750
Head Dia., A
Min.,
Max.,
Edge
Edge
Rounded
Sharp
or Flat
0.043
0.037
0.064
0.058
0.093
0.085
0.119
0.096
0.146
0.120
0.172
0.143
0.199
0.167
0.225
0.191
0.279
0.238
0.332
0.285
0.385
0.333
0.507
0.442
0.635
0.556
0.762
0.670
Head
Height,
H
Ref.
0.009
0.014
0.020
0.026
0.031
0.037
0.043
0.049
0.060
0.072
0.083
0.110
0.138
0.165
Slot
Width,
J
Max.
0.008
0.012
0.017
0.023
0.026
0.031
0.035
0.039
0.048
0.054
0.060
0.075
0.084
0.094
Min.
0.005
0.008
0.010
0.016
0.019
0.023
0.027
0.031
0.039
0.045
0.050
0.064
0.072
0.081
Slot
Depth,
T
Max.
0.008
0.011
0.013
0.013
0.016
0.019
0.022
0.024
0.030
0.036
0.042
0.055
0.069
0.083
Min.
0.004
0.007
0.008
0.008
0.010
0.012
0.014
0.017
0.022
0.027
0.031
0.042
0.053
0.065
a When specifying nominal size in decimals, zeros preceding the decimal point and in the fourth decimal place are omitted.
All dimensions are in inches.
MACHINE SCREWS
1589
Table 3. American National Standard Slotted Flat Countersunk Head and Close
Tolerance 100-Degree Flat Countersunk Head Machine Screws
ANSI B18.6.3-1972 (R1991)
Nominal
Sizea or Basic
Screw Dia.
0000
000
00
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
Max.,
Lb
0.0210
0.0340
0.0470
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
SLOTTED FLAT COUNTERSUNK HEAD TYPE
Head Dia., A
Head
Slot
Height, H
Width, J
Min.,
Max., Edge
c
Sharp
Edge
Ref.
Max.
Min.
....
....
....
1⁄
8
1⁄
8
1⁄
8
1⁄
8
3⁄
16
3⁄
16
3⁄
16
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
…
…
…
0.043
0.064
0.093
0.119
0.146
0.172
0.199
0.225
0.252
0.279
0.332
0.385
0.438
0.507
0.635
0.762
0.812
0.875
1.000
1.125
1.375
0.037
0.058
0.085
0.099
0.123
0.147
0.171
0.195
0.220
0.244
0.292
0.340
0.389
0.452
0.568
0.685
0.723
0.775
0.889
1.002
1.230
0.011
0.016
0.028
0.035
0.043
0.051
0.059
0.067
0.075
0.083
0.100
0.116
0.132
0.153
0.191
0.230
0.223
0.223
0.260
0.298
0.372
0.008
0.011
0.017
0.023
0.026
0.031
0.035
0.039
0.043
0.048
0.054
0.060
0.067
0.075
0.084
0.094
0.094
0.106
0.118
0.133
0.149
0.004
0.007
0.010
0.016
0.019
0.023
0.027
0.031
0.035
0.039
0.045
0.050
0.056
0.064
0.072
0.081
0.081
0.091
0.102
0.116
0.131
Slot
Depth, T
Max.
Min.
0.007
0.009
0.014
0.015
0.019
0.023
0.027
0.030
0.034
0.038
0.045
0.053
0.060
0.070
0.088
0.106
0.103
0.103
0.120
0.137
0.171
0.003
0.005
0.009
0.010
0.012
0.015
0.017
0.020
0.022
0.024
0.029
0.034
0.039
0.046
0.058
0.070
0.066
0.065
0.077
0.088
0.111
b These lengths or shorter are undercut.
c May be rounded or flat.
CLOSE TOLERANCE 100-DEGREE FLAT COUNTERSUNK HEAD TYPE
Head Diameter, A
Head
Slot
Height,
Width,
Max.,
Min.,
H
J
Edge
Edgec
Sharp
Ref.
Max.
Min.
Nominal
Sizea
or Basic
Screw Dia.
4
6
8
10
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
Slot
Depth,
T
Max.
Min.
0.1120
0.1380
0.1640
0.1900
0.2500
0.225
0.279
0.332
0.385
0.507
0.191
0.238
0.285
0.333
0.442
0.049
0.060
0.072
0.083
0.110
0.039
0.048
0.054
0.060
0.075
0.031
0.039
0.045
0.050
0.064
0.024
0.030
0.036
0.042
0.055
0.017
0.022
0.027
0.031
0.042
0.3125
0.635
0.556
0.138
0.084
0.072
0.069
0.053
0.3750
0.762
0.670
0.165
0.094
0.081
0.083
0.065
0.4375
0.890
0.783
0.193
0.094
0.081
0.097
0.076
0.5000
1.017
0.897
0.221
0.106
0.091
0.111
0.088
0.5625
1.145
1.011
0.249
0.118
0.102
0.125
0.099
0.6250
1.272
1.124
0.276
0.133
0.116
0.139
0.111
1590
MACHINE SCREWS
Table 4. American National Standard Slotted Undercut Flat Countersunk Head and
Plain and Slotted Hex Washer Head Machine Screws ANSI B18.6.3-1972 (R1991)
SLOTTED UNDERCUT FLAT COUNTERSUNK HEAD TYPE
Nominal
Sizea or Basic
Screw Dia.
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.3125
0.3750
0.4375
0.5000
Max.,
Lb
1⁄
8
1⁄
8
1⁄
8
1⁄
8
3⁄
16
3⁄
16
3⁄
16
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
Head Dia., A
Max.,
Min., Edge
Edge
Rnded.
Sharp
or Flat
Head
Height,
H
Max.
Min.
Slot
Width,
J
Max.
Min.
Slot
Depth,
T
Max.
Min.
0.119
0.146
0.172
0.199
0.225
0.252
0.279
0.332
0.099
0.123
0.147
0.171
0.195
0.220
0.244
0.292
0.025
0.031
0.036
0.042
0.047
0.053
0.059
0.070
0.018
0.023
0.028
0.033
0.038
0.043
0.048
0.058
0.023
0.026
0.031
0.035
0.039
0.043
0.048
0.054
0.016
0.019
0.023
0.027
0.031
0.035
0.039
0.045
0.011
0.014
0.016
0.019
0.022
0.024
0.027
0.032
0.007
0.009
0.011
0.012
0.014
0.016
0.017
0.021
0.385
0.438
0.507
0.635
0.762
0.340
0.389
0.452
0.568
0.685
0.081
0.092
0.107
0.134
0.161
0.068
0.078
0.092
0.116
0.140
0.060
0.067
0.075
0.084
0.094
0.050
0.056
0.064
0.072
0.081
0.037
0.043
0.050
0.062
0.075
0.024
0.028
0.032
0.041
0.049
0.812
0.875
0.723
0.775
0.156
0.156
0.133
0.130
0.094
0.106
0.081
0.091
0.072
0.072
0.045
0.046
PLAIN AND SLOTTED HEX WASHER HEAD TYPES
Nominal
Sizea
or Basic
Screw Dia.
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
Width
Across
Flats,
A
Max. Min.
Width
AcrossCorn.,
W
Min.
Head
Height,
H
Washer
Dia.,
B
Washer
Thick.,
U
Slota
Width,
J
Slota
Depth,
T
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.125
0.125
0.188
0.188
0.250
0.250
0.312
0.312
0.375
0.120
0.120
0.181
0.181
0.244
0.244
0.305
0.305
0.367
0.134
0.134
0.202
0.202
0.272
0.272
0.340
0.340
0.409
0.050
0.055
0.060
0.070
0.093
0.110
0.120
0.155
0.190
0.040
0.044
0.049
0.058
0.080
0.096
0.105
0.139
0.172
0.166
0.177
0.243
0.260
0.328
0.348
0.414
0.432
0.520
0.154
0.163
0.225
0.240
0.302
0.322
0.384
0.398
0.480
0.016
0.016
0.019
0.025
0.025
0.031
0.031
0.039
0.050
0.010
0.010
0.011
0.015
0.015
0.019
0.019
0.022
0.030
….
….
0.039
0.043
0.048
0.054
0.060
0.067
0.075
….
….
0.031
0.035
0.039
0.045
0.050
0.056
0.064
….
….
0.042
0.049
0.053
0.074
0.080
0.103
0.111
….
….
0.025
0.030
0.033
0.052
0.057
0.077
0.083
0.3125
0.500 0.489
0.545
0.230 0.208 0.676 0.624 0.055 0.035 0.084 0.072 0.134 0.100
0.3750
0.562 0.551
0.614
0.295 0.270 0.780 0.720 0.063 0.037 0.094 0.081 0.168 0.131
a Unless otherwise specified, hexagon washer head machine screws are not slotted.
MACHINE SCREWS
1591
Table 5. American National Standard Slotted Truss Head and Plain and Slotted
Hexagon Head Machine Screws ANSI B18.6.3-1972 (R1991)
SLOTTED TRUSS HEAD TYPE
Head Dia.,
A
Min.
Nominal
Sizea or Basic
Screw Dia.
0000
000
00
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
Max.
0.0210
0.0340
0.0470
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
0.049
0.077
0.106
0.131
0.164
0.194
0.226
0.257
0.289
0.321
0.384
0.448
0.511
0.573
0.698
0.823
0.948
1.073
1.198
1.323
1.573
0.043
0.071
0.098
0.119
0.149
0.180
0.211
0.241
0.272
0.303
0.364
0.425
0.487
0.546
0.666
0.787
0.907
1.028
1.149
1.269
1.511
Head Height,
H
Min.
Max.
0.014
0.022
0.030
0.037
0.045
0.053
0.061
0.069
0.078
0.086
0.102
0.118
0.134
0.150
0.183
0.215
0.248
0.280
0.312
0.345
0.410
0.010
0.018
0.024
0.029
0.037
0.044
0.051
0.059
0.066
0.074
0.088
0.103
0.118
0.133
0.162
0.191
0.221
0.250
0.279
0.309
0.368
Head Radius,
R
Max.
Max.
Slot Width,
J
Min.
0.032
0.051
0.070
0.087
0.107
0.129
0.151
0.169
0.191
0.211
0.254
0.283
0.336
0.375
0.457
0.538
0.619
0.701
0.783
0.863
1.024
0.009
0.013
0.017
0.023
0.026
0.031
0.035
0.039
0.043
0.048
0.054
0.060
0.067
0.075
0.084
0.094
0.094
0.106
0.118
0.133
0.149
Slot Depth,
T
Min.
Max.
0.005
0.009
0.010
0.016
0.019
0.023
0.027
0.031
0.035
0.039
0.045
0.050
0.056
0.064
0.072
0.081
0.081
0.091
0.102
0.116
0.131
0.009
0.013
0.018
0.022
0.027
0.031
0.036
0.040
0.045
0.050
0.058
0.068
0.077
0.087
0.106
0.124
0.142
0.161
0.179
0.196
0.234
0.005
0.009
0.012
0.014
0.018
0.022
0.026
0.030
0.034
0.037
0.045
0.053
0.061
0.070
0.085
0.100
0.116
0.131
0.146
0.162
0.182
a Where specifying nominal size in decimals, zeros preceding decimal points and in the fourth decimal place are omitted.
PLAIN AND SLOTTED HEXAGON HEAD TYPES
Regular Head
Width
Across
Across
Corn., W
Flats, A
Max. Min.
Min.
Large Head
Width
Across
Across
Corn., W
Flats, A
Max. Min.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
.125
.125
.188
.188
.188
.250
.250
.312
.312
.375
.120
.120
.181
.181
.181
.244
.244
.305
.305
.367
.134
.134
.202
.202
.202
.272
.272
.340
.340
.409
....
....
....
.219
.250
....
.312
....
.375
.438
....
....
....
.213
.244
....
.305
....
.367
.428
....
....
....
.238
.272
....
.340
....
.409
.477
.044
.050
.055
.060
.070
.093
.110
.120
.155
.190
.036
.040
.044
.049
.058
.080
.096
.105
.139
.172
....
....
....
.039
.043
.048
.054
.060
.067
.075
....
....
....
.031
.035
.039
.045
.050
.056
.064
....
....
....
.036
.042
.046
.066
.072
.093
.101
…
…
…
.02
.03
.03
.05
.057
.07
.08
0.3125
.500
.489
.545
....
....
....
.230
.208
.084
.072
.122
.10
0.3750
.562
.551
.614
....
....
....
.295
.270
.094
.081
.156
.13
Nominal
Sizea
or Basic
Screw Dia.
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
Head
Height, H
Slota
Width, J
a Unless otherwise specified, hexagon head machine screws are not slotted.
Slota
Depth, T
1592
MACHINE SCREWS
Table 6. American National Standard Slotted Pan Head Machine Screws
ANSI B18.6.3-1972 (R1991)
Head
Dia.,
A
Nominal
Sizea
or Basic
Screw Dia.
0000
000
00
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
0.0210
0.0340
0.0470
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
Max.
Min.
Head
Height,
H
Max.
Min.
.042
.066
.090
.116
.142
.167
.193
.219
.245
.270
.322
.373
.425
.492
.615
.740
.863
.987
1.041
1.172
1.435
.036
.060
.082
.104
.130
.155
.180
.205
.231
.256
.306
.357
.407
.473
.594
.716
.837
.958
1.000
1.125
1.375
.016
.023
.032
.039
.046
.053
.060
.068
.075
.082
.096
.110
.125
.144
.178
.212
.247
.281
.315
.350
.419
.010
.017
.025
.031
.038
.045
.051
.058
.065
.072
.085
.099
.112
.130
.162
.195
.228
.260
.293
.325
.390
Head
Radius,
R
Max.
.007
.010
.015
.020
.025
.035
.037
.042
.044
.046
.052
.061
.078
.087
.099
.143
.153
.175
.197
.219
.263
Slot
Width,
J
Max.
Min.
Slot
Depth,
T
Max.
Min.
.008
.012
.017
.023
.026
.031
.035
.039
.043
.048
.054
.060
.067
.075
.084
.094
.094
.106
.118
.133
.149
.008
.012
.016
.022
.027
.031
.036
.040
.045
.050
.058
.068
.077
.087
.106
.124
.142
.161
.179
.197
.234
.004
.008
.010
.016
.019
.023
.027
.031
.035
.039
.045
.050
.056
.064
.072
.081
.081
.091
.102
.116
.131
.004
.008
.010
.014
.018
.022
.026
.030
.034
.037
.045
.053
.061
.070
.085
.100
.116
.131
.146
.162
.192
a Where specifying nominal size in decimals, zeros preceding decimal and in the fourth decimal
place are omitted.
Table 7. Nos. 0000, 000 and 00 Threads ANSI B18.6.3-1972 (R1991) Appendix
Series
Designat.
Class
Externalb
Nominal
Sizea
and
Threads
Per Inch
0000-160 or
0.0210-160
NS
2
.0210 .0195 .0169 .0158
000-120 or
0.0340-120
NS
2
00-90 or
0.0470-90
NS
00-96 or
0.0470-96
NS
Internalc
Pitch
Diameter
Minor
Dia.
Class
Major
Diameter
.0011
.0128
.0340 .0325 .0286 0.272
.0014
2
.0470 .0450 .0398 .0382
2
.0470 .0450 .0402 .0386
Max.
Min.
Max.
Min.
Tol.
Pitch
Diameter
Major
Dia.
Min.
Max.
Tol.
Min.
2
.0169
.0181
.0012
.0210
.0232
2
.0286
.0300
.0014
.034
.0016
.0326
2
.0398
.0414
.0016
.047
.0016
.0334
2
.0402
.0418
.0016
.047
a Where
specifying nominal size in decimals, zeros preceding decimal and in the fourth decimal
place are omitted.
b There is no allowance provided on the external threads.
c The minor diameter limits for internal threads are not specified, they being determined by the
amount of thread engagement necessary to satisfy the strength requirements and tapping performance
in the intended application.
MACHINE SCREWS
1593
Table 8. American National Standard Slotted Fillister and Slotted Drilled
Fillister Head Machine Screws ANSI B18.6.3-1972 (R1991)
SLOTTED FILLISTER HEAD TYPE
0000
000
00
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
Head Side
Height,
H
Head Dia.,
A
Nominal
Size1 or Basic
Screw Dia.
Total Head
Height,
O
Slot Width,
J
Slot Depth,
T
Max.
Min.
Max.
Min.
Max.
Min.
Max
Min.
Max.
Min.
0.0210
0.0340
0.0470
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
.038
.059
.082
.096
.118
.140
.161
.183
.205
.226
.270
.313
.357
.414
.032
.053
.072
.083
.104
.124
.145
.166
.187
.208
.250
.292
.334
.389
.019
.029
.037
.043
.053
.062
.070
.079
.088
.096
.113
.130
.148
.170
.011
.021
.028
.038
.045
.053
.061
.069
.078
.086
.102
.118
.134
.155
.025
.035
.047
.055
.066
.083
.095
.107
.120
.132
.156
.180
.205
.237
.15
.027
.039
.047
.058
.066
.077
.088
.100
.111
.133
.156
.178
.207
.008
.012
.017
.023
.026
.031
.035
.039
.043
.048
.054
.060
.067
.075
.004
.006
.010
.016
.019
.023
.027
.031
.035
.039
.045
.050
.056
.064
.012
.017
.022
.025
.031
.037
.043
.048
.054
.060
.071
.083
.094
.109
.006
.011
.015
.015
.020
.025
.030
.035
.040
.045
.054
.064
.074
.087
0.3125
.518
.490
.211
.194
.295
.262
.084
.072
.137
.110
0.3750
.622
.590
.253
.233
.355
.315
.094
.081
.164
.133
0.4375
.625
.589
.265
.242
.368
.321
.094
.081
.170
.135
0.5000
.750
.710
.297
.273
.412
.362
.106
.091
.190
.151
0.5625
.812
.768
.336
.308
.466
.410
.118
.102
.214
.172
0.6250
.875
.827
.375
.345
.521
.461
.133
.116
.240
.193
0.7500
1.000
.945
.441
.406
.612
.542
.149
.131
.281
.226
Drilled
Hole
Locat.,
E
Drilled
Hole.
Dia.,
F
SLOTTED DRILLED FILLISTER HEAD TYPE
Nominal
Size1
or Basic
Screw Dia.
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
Head
Dia.,
A
Head
Side
Height,
H
Total
Head
Height,
O
Slot
Width,
J
Slot
Depth,
T
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Basic
Basic
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
.140
.161
.183
.205
.226
.270
.313
.357
.414
.124
.145
.166
.187
.208
.250
.292
.334
.389
.062
.070
.079
.088
.096
.113
.130
.148
.170
.055
.064
.072
.081
.089
.106
.123
.139
.161
.083
.095
.107
.120
.132
.156
.180
.205
.237
.070
.082
.094
.106
.118
.141
.165
.188
.219
.031
.035
.039
.043
.048
.054
.060
.067
.075
.023
.027
.031
.035
.039
.045
.050
.056
.064
.030
.034
.038
.042
.045
.065
.075
.087
.102
.022
.026
.030
.033
.035
.054
.064
.074
.087
.026
.030
.035
.038
.043
.043
.043
.053
.062
.031
.037
.037
.046
.046
.046
.046
.046
.062
0.3125
.518
.490
.211
.201
.295
.276
.084
.072
.130
.110
.078
.070
0.3750
.622
.590
.253
.242
.355
.333
.094
.081
.154
.134
.094
.070
1Where specifying nominal size in decimals, zeros preceding decimal points and in the fourth decimal place are omitted.
2Drilled hole shall be approximately perpendicular to the axis of slot and may be permitted to break
through bottom of the slot. Edges of the hole shall be free from burrs.
3A slight rounding of the edges at periphery of head is permissible provided the diameter of the
bearing circle is equal to no less than 90 per cent of the specified minimum head diameter.
1594
MACHINE SCREWS
Table 9. American National Standard Slotted Oval Countersunk
Head Machine Screws ANSI B18.6.3-1972 (R1991)
Max
Lb
Nominal
Sizea
or Basic
Screw Dia.
00
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
0.0470
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
…
1⁄
8
1⁄
8
1⁄
8
1⁄
8
3⁄
16
3⁄
16
3⁄
16
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
…
…
…
Head Dia.,
A
Min.,
Edge
Rnded.
or Flat
Head
Side
Height,
H,
Max.,
Edge
Sharp
.093
.119
.146
.172
.199
.225
.252
.279
.332
.385
.438
.507
.635
.762
.812
.875
1.000
1.125
1.375
.085
.099
.123
.147
.171
.195
.220
.244
.292
.340
.389
.452
.568
.685
.723
.775
.889
1.002
1.230
Total Head
Height,
O
Slot
Width,
J
Slot
Depth,
T
Ref.
Max.
Min.
Max.
Min.
Max.
Min.
.028
.035
.043
.051
.059
.067
.075
.083
.100
.116
.132
.153
.191
.230
.223
.223
.260
.298
.372
.042
.056
.068
.080
.092
.104
.116
.128
.152
.176
.200
.232
.290
.347
.345
.354
.410
.467
.578
.034
.041
.052
.063
.073
.084
.095
.105
.126
.148
.169
.197
.249
.300
.295
.299
.350
.399
.497
.017
.023
.026
.031
.035
.039
.043
.048
.054
.060
.067
.075
.084
.094
.094
.106
.118
.133
.149
.010
.016
.019
.023
.027
.031
.035
.039
.045
.050
.056
.064
.072
.081
.081
.091
.102
.116
.131
.023
.030
.038
.045
.052
.059
.067
.074
.088
.103
.117
.136
.171
.206
.210
.216
.250
.285
.353
.016
.025
.031
.037
.043
.049
.055
.060
.072
.084
.096
.112
.141
.170
.174
.176
.207
.235
.293
a When specifying nominal size in decimals, zeros preceding decimal points and in the fourth decimal place are omitted.
Table 10. American National Standard Header Points for
Machine Screws before Threading ANSI B18.6.3-1972 (R1991)
Nom.
Size
Threads
per Inch
Max.
P
Min.
P
24
0.125
0.112
32
0.138
0.124
24
28
20
28
18
24
16
24
14
20
13
20
0.149
0.156
0.170
0.187
0.221
0.237
0.270
0.295
0.316
0.342
0.367
0.399
0.134
0.141
0.153
0.169
0.200
0.215
0.244
0.267
0.287
0.310
0.333
0.362
11⁄4
10
Nom.
Size.
2
4
5
6
8
Threads
per Inch
56
64
40
48
40
44
32
40
32
36
Max.
P
0.057
0.060
0.074
0.079
0.086
0.088
0.090
0.098
0.114
0.118
Min.
P
0.050
0.053
0.065
0.070
0.076
0.079
0.080
0.087
0.102
0.106
Max.
L
12
1⁄
2
1⁄
4
1⁄
2
5⁄
16
1⁄
2
3⁄
8
3⁄
4
7⁄
16
1
1⁄
2
Max.
L
13⁄8
11⁄2
11⁄2
11⁄2
11⁄2
11⁄2
All dimensions in inches. Edges of point may be rounded and end of point need not be flat nor perpendicular to shank. Machine screws normally have plain sheared ends but when specified may have
header points, as shown above.
MACHINE SCREWS
1595
Table 11. American National Standard Slotted Binding Head and Slotted Undercut
Oval Countersunk Head Machine Screws ANSI B18.6.3-1972 (R1991)
Nominal
Sizea
or Basic
Screw Dia.
0000
000
00
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
0.0210
0.0340
0.0470
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.3125
0.3750
SLOTTED BINDING HEAD TYPE
Slot
Head Oval
Width,
Height,
J
F
Max. Min. Max. Min.
Slot
Depth,
T
Max. Min.
Undercutb
Dia.,
U
Max. Min.
Undercutb
Depth,
X
Max. Min.
.009
.015
.023
.026
.035
.043
.052
.061
.069
.078
.095
.112
.130
.152
.194
.235
.009
.013
.018
.018
.024
.030
.036
.042
.048
.053
.065
.077
.089
.105
.134
.163
…
…
…
.098
.120
.141
.162
.184
.205
.226
.269
.312
.354
.410
.513
.615
…
…
…
.007
.008
.010
.011
.012
.014
.015
.017
.020
.023
.026
.032
.039
Head
Dia.,
A
Max. Min.
Total Head
Height,
O
Max. Min.
.046
.073
.098
.126
.153
.181
.208
.235
.263
.290
.344
.399
.454
.525
.656
.788
.014
.021
.028
.032
.041
.050
.059
.068
.078
.087
.105
.123
.141
.165
.209
.253
.040
.067
.090
.119
.145
.171
.197
.223
.249
.275
.326
.378
.430
.498
.622
.746
.006
.008
.011
.012
.015
.018
.022
.025
.029
.032
.039
.045
.052
.061
.077
.094
.003
.005
.007
.008
.011
.013
.016
.018
.021
.024
.029
.034
.039
.046
.059
.071
.008
.012
.017
.023
.026
.031
.035
.039
.043
.048
.054
.060
.067
.075
.084
.094
.004
.006
.010
.016
.019
.023
.027
.031
.035
.039
.045
.050
.056
.064
.072
.081
.005
.009
.012
.009
.014
.020
.025
.030
.035
.040
.050
.060
.070
.084
.108
.132
…
…
…
.086
.105
.124
.143
.161
.180
.199
.236
.274
.311
.360
.450
.540
…
…
…
.002
.003
.005
.006
.007
.009
.010
.012
.015
.018
.021
.027
.034
a Where specifying nominal size in decimals, zeros preceding decimal points and in the fourth decimal place are omitted.
b Unless otherwise specified, slotted binding head machine screws are not undercut.
Nominal
Sizea
or Basic
Screw Dia.
0
0.0600
1
0.0730
2
0.0860
3
0.0990
4
0.1120
5
0.1250
6
0.1380
8
0.1640
10
0.1900
12
0.2160
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
0.2500
0.3125
0.3750
0.4375
0.5000
SLOTTED UNDERCUT OVAL COUNTERSUNK HEAD TYPES
Total
Head Dia.,
Head
Head
Slot
A
Side
Height,
Width,
Height,
Min.,
O
J
H
Edge
Max.,
Max.
Rnded.
Edge
or Flat
Ref.
Max.
Min.
Max.
Min.
Sharp
La
1⁄
8
1⁄
8
1⁄
8
1⁄
8
3⁄
16
3⁄
16
3⁄
16
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
Slot
Depth,
T
Max.
Min.
.119
.099
.025
.046
.033
.023
.016
.028
.022
.146
.123
.031
.056
.042
.026
.019
.034
.027
.172
.147
.036
.065
.050
.031
.023
.040
.033
.199
.171
.042
.075
.059
.035
.027
.047
.038
.225
.195
.047
.084
.067
.039
.031
.053
.043
.252
.220
.053
.094
.076
.043
.035
.059
.048
.279
.244
.059
.104
.084
.048
.039
.065
.053
.332
.292
.070
.123
.101
.054
.045
.078
.064
.385
.340
.081
.142
.118
.060
.050
.090
.074
.438
.389
.092
.161
.135
.067
.056
.103
.085
.507
.452
.107
.186
.158
.075
.064
.119
.098
.635
.568
.134
.232
.198
.084
.072
.149
.124
.762
.685
.161
.278
.239
.094
.081
.179
.149
.812
.723
.156
.279
.239
.094
.081
.184
.154
.875
.775
.156
.288
.244
.106
.091
.204
.169
a These lengths or shorter are undercut.
1596
MACHINE SCREWS
Table 12. Slotted Round Head Machine Screws
ANSI B18.6.3-1972 (R1991) Appendix
Nominal
Sizea or Basic
Screw Dia.
0000
000
00
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
0.0210
0.0340
0.0470
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
Head Diameter,
A
Min.
.035
.056
.080
.099
.122
.146
.169
.193
.217
.240
.287
.334
.382
.443
.557
.670
.707
.766
.887
.944
1.185
Max.
.041
.062
.089
.113
.138
.162
.187
.211
.236
.260
.309
.359
.408
.472
.590
.708
.750
.813
.938
1.000
1.250
Head Height,
H
Min.
.016
.025
.036
.043
.051
.059
.067
.075
.083
.091
.107
.123
.139
.160
.198
.237
.307
.332
.385
.411
.516
Max.
.022
.031
.045
.053
.061
.069
.078
.086
.095
.103
.120
.137
.153
.175
.216
.256
.328
.355
.410
.438
.547
Slot Width,
J
Min.
.004
.008
.010
.016
.019
.023
.027
.031
.035
.039
.045
.050
.056
.064
.072
.081
.081
.091
.102
.116
.131
Max.
.008
.012
.017
.023
.026
.031
.035
.039
.043
.048
.054
.060
.067
.075
.084
.094
.094
.106
.118
.133
.149
Slot Depth,
T
Min.
.013
.012
.018
.029
.033
.037
.040
.044
.047
.051
.058
.065
.073
.082
.099
.117
.148
.159
.183
.195
.242
Max.
.017
.018
.026
.039
.044
.048
.053
.058
.063
.068
.077
.087
.096
.109
.132
.155
.196
.211
.242
.258
.320
a When specifying nominal size in decimals, zeros preceding decimal point and in the fourth decimal
place are omitted.
Not recommended, use Pan Head machine screws.
ANSI Cross References for Machine Screws and Metric Machine Screw
Type I Cross Recess
Type IA Cross Recess
Type II Cross Recess
Type III Square Center
Machine Screw Cross Recesses.—Four cross recesses, Types I, IA, II, and III, may be
used in lieu of slots in machine screw heads. Dimensions for recess diameter M, width N,
and depth T (not shown above) together with recess penetration gaging depths are given in
American National Standard ANSI B18.6.3-1972 (R1991) for machine screws, and in
ANSI/ASME B18.6.7M-1985 for metric machine screws.
American National Standard Metric Machine Screws.—This Standard B18.6.7M
covers metric flat and oval countersunk and slotted and recessed pan head machine screws
and metric hex head and hex flange head machine screws. Dimensions are given in Tables
1 through 4 and 6.
MACHINE SCREWS
1597
Table 1. American National Standard Thread Lengths for Metric Machine Screws
ANSI/ASME B18.6.7M-1985
Pan, Hex, and Hex Flange Head
Screws
L
LUS
Flat and Oval Countersunk Head
Screws
LU
LUS
L
Nominal
Screw
Lengtha
Heat-Treated Recessed Flat
Countersunk Head Screws
LU L
L
Nominal
Screw
Size
and
Thread
Pitch
Nominal
Screw
Length
Equal
to or
Shorter
thana
Maxd
Maxe
Over
To and
Including
Maxd
Maxe
Nominal
Screw
Length
Longer
thana
M2 × 0.4
M2.5 × 0.45
M3 × 0.5
M3.5 × 0.6
M4 × 0.7
M5 × 0.8
M6 × 1
M8 × 1.25
M10 × 1.5
M12 × 1.75
6
8
9
10
12
15
18
24
30
36
1.0
1.1
1.2
1.5
1.8
2.0
2.5
3.1
3.8
4.4
0.4
0.5
0.5
0.6
0.7
0.8
1.0
1.2
1.5
1.8
6
8
9
10
12
15
18
24
30
36
30
30
30
50
50
50
50
50
50
50
1.0
1.1
1.2
1.5
1.8
2.0
2.5
3.1
3.8
4.4
0.8
0.9
1.0
1.2
1.4
1.6
2.0
2.5
3.0
3.5
30
30
30
50
50
50
50
50
50
50
Unthreaded
Lengthb
Unthreaded
Lengthb
B
Full
Form
Thread
Lengthc
Min
25.0
25.0
25.0
38.0
38.0
38.0
38.0
38.0
38.0
38.0
a The length tolerances for metric machine screws are: up to 3 mm, incl., ± 0.2 mm; over 3 to 10 mm,
incl., ± 0.3 mm; over 10 to 16 mm, incl., ± 0.4 mm; over 16 to 50 mm, incl., ± 0.5 mm; over 50 mm, ±
1.0 mm.
b Unthreaded lengths L and L
U
US represent the distance, measured parallel to the axis of screw, from
the underside of the head to the face of a nonchamfered or noncounterbored standard GO thread ring
gage assembled by hand as far as the thread will permit.
c Refer to the illustrations for respective screw head styles.
d The L
US values apply only to heat treated recessed flat countersunk head screws.
e The L values apply to all screws except heat treated recessed flat countersunk head screws.
U
All dimensions in millimeters.
Slotted and Style A
Body Diameter
Body and
Shoulder
Diameter
LSHa
DS
Shoulder
Diameter
Body
Diameter
DK
K
Head Diameter
Shoulder
Length
Theoretical
Sharp
Actual
Head
Height
Max
Min
Max
Min
Min
Max
Min
Max
Min
Min
Max
Ref
M2 × 0.4b
2.00
1.65
2.00
1.86
1.65
0.50
0.30
4.4
4.1
3.5
1.2
M2.5 × 0.45
2.50
2.12
2.50
2.36
2.12
0.55
0.35
5.5
5.1
4.4
1.5
R
N
Underhead
Fillet
Radius
T
Slot
Width
Slot
Depth
Max
Min
Max
Min
Max
0.8
0.4
0.7
0.5
0.6
Min
0.4
1.0
0.5
0.8
0.6
0.7
0.5
M3 × 0.5
3.00
2.58
3.00
2.86
2.58
0.60
0.40
6.3
5.9
5.2
1.7
1.2
0.6
1.0
0.8
0.9
0.6
M3.5 × 0.6
3.50
3.00
3.50
3.32
3.00
0.70
0.50
8.2
7.7
6.9
2.3
1.4
0.7
1.2
1.0
1.2
0.9
M4 × 0.7
4.00
3.43
4.00
3.82
3.43
0.80
0.60
9.4
8.9
8.0
2.7
1.6
0.8
1.5
1.2
1.3
1.0
M5 × 0.8
5.00
4.36
5.00
4.82
4.36
0.90
0.70
10.4
9.8
8.9
2.7
2.0
1.0
1.5
1.2
1.4
1.1
M6 × 1
6.00
5.21
6.00
5.82
5.21
1.10
0.90
12.6
11.9
10.9
3.3
2.4
1.2
1.9
1.6
1.6
1.2
M8 × 1.25
8.00
7.04
8.00
7.78
7.04
1.40
1.10
17.3
16.5
15.4
4.6
3.2
1.6
2.3
2.0
2.3
1.8
M10 × 1.5
10.00
8.86
10.00
9.78
8.86
1.70
1.30
20.0
19.2
17.8
5.0
4.0
2.0
2.8
2.5
2.6
2.0
a All
recessed head heat-treated steel screws of property class 9.8 or higher strength have the Style B head form. Recessed head screws other than those specifically
designated to be Style B have the Style A head form. The underhead shoulder on the Style B head form is mandatory and all other head dimensions are common to both
the Style A and Style B head forms.
b This size is not specified for Type III square recessed flat countersunk heads; Type II cross recess is not specified for any size.
For dimension B, see Table 1.
For dimension L, see Table 7.
MACHINE SCREWS
Nominal
Screw
Size
and
Thread
Pitch
Style B
DSHa
DS
1598
Table 2. American National Standard Slotted, Cross and Square Recessed Flat Countersunk Head Metric Machine Screws
Table 3. American National Standard Slotted, Cross and Square Recessed Oval Countersunk Head Metric Machine Screws
DK
K
F
RF
R
N
T
Actual
Head
Side
Height
Raised
Head
Height
Head
Top
Radius
Underhead
Fillet
Radius
Slot
Width
Slot
Depth
Head Diameter
Theoretical
Sharp
Body
Diameter
Min
Max
Min
Min
Max
Ref
Max
Approx
Max
Min
Max
Min
Max
M2 × 0.4a
2.00
1.65
4.4
4.1
3.5
1.2
0.5
5.0
0.8
0.4
0.7
0.5
1.0
0.8
M2.5 × 0.45
2.50
2.12
5.5
4.4
1.5
0.6
6.6
1.0
0.5
0.8
0.6
1.2
1.0
Max
5.1
Min
M3 × 0.5
3.00
2.58
6.3
5.9
5.2
1.7
0.7
7.4
1.2
0.6
1.0
0.8
1.5
1.2
M3.5 × 0.6
3.50
3.00
8.2
7.7
6.9
2.3
0.8
10.9
1.4
0.7
1.2
1.0
1.7
1.4
M4 × 0.7
4.00
3.43
9.4
8.9
8.0
2.7
1.0
11.6
1.6
0.8
1.5
1.2
1.9
1.6
M5 × 0.8
5.00
4.36
10.4
9.8
8.9
2.7
1.2
11.9
2.0
1.0
1.5
1.2
2.4
2.0
M6 × 1
6.00
5.21
12.6
11.9
10.9
3.3
1.4
14.9
2.4
1.2
1.9
1.6
2.8
2.4
M8 × 1.25
8.00
7.04
17.3
16.5
15.4
4.6
2.0
19.7
3.2
1.6
2.3
2.0
3.7
3.2
M10 × 1.5
10.00
8.86
20.0
19.2
17.8
5.0
2.3
22.9
4.0
2.0
2.8
2.5
4.4
3.8
MACHINE SCREWS
DS
Nominal
Screw
Size
and
Thread
Pitch
a This size is not specified for Type III square recessed oval countersunk heads; Type II cross recess is not specified for any size.
1599
M2 × 0.4a
M2.5 × 0.45
M3 × 0.5
M3.5 × 0.6
M4 × 0.7
M5 × 0.8
M6 × 1
M8 × 1.25
M10 × 1.5
Ds
DK
R1
K
Body
Diameter
Max
Min
Head
Diameter
Max
Min
Head
Height
Max
Min
2.00
2.50
3.00
3.50
4.00
5.00
6.00
8.00
10.00
4.0
5.0
5.6
7.0
8.0
9.5
12.0
16.0
20.0
1.3
1.5
1.8
2.1
2.4
3.0
3.6
4.8
6.0
1.65
2.12
2.58
3.00
3.43
4.36
5.21
7.04
8.86
3.7
4.7
5.3
6.6
7.6
9.1
11.5
15.5
19.4
1.1
1.3
1.6
1.9
2.2
2.7
3.3
4.5
5.7
Head
Radius
Max
0.8
1.0
1.2
1.4
1.6
2.0
2.5
3.2
4.0
R1
K
Head
Height
Max
Min
1.6
2.1
2.4
2.6
3.1
3.7
4.6
6.0
7.5
1.4
1.9
2.2
2.3
2.8
3.4
4.3
5.6
7.1
Head
Radius
Ref
3.2
4.0
5.0
6.0
6.5
8.0
10.0
13.0
16.0
DA
R
Underhead Fillet
Transition
Dia
Radius
Max
Min
2.6
3.1
3.6
4.1
4.7
5.7
6.8
9.2
11.2
a This size not specified for Type III square recessed pan heads; Type II cross recess is not specified for any size.
0.1
0.1
0.1
0.1
0.2
0.2
0.3
0.4
0.4
N
Slot
Width
Max
Min
0.7
0.8
1.0
1.2
1.5
1.5
1.9
2.3
2.8
0.5
0.6
0.8
1.0
1.2
1.2
1.6
2.0
2.5
T
W
Slot
Depth
Min
Unslotted
Head
Thickness
Min
0.5
0.6
0.7
0.8
1.0
1.2
1.4
1.9
2.4
0.4
0.5
0.7
0.8
0.9
1.2
1.4
1.9
2.4
MACHINE SCREWS
Cross and
Square Recess
Slotted
Nominal
Screw
Size
and
Thread
Pitch
1600
Table 4. American National Standard Slotted and Cross and Square Recessed Pan Head Metric Machine Screws
METRIC MACHINE SCREWS
1601
Table 5. American National Standard Header Points for Metric Machine Screws
Before Threading ANSI/ASME B18.6.7M-1985
Nominal Screw Size
and Thread
Pitch
M2 × 0.4
M2.5 × 0.45
M3 × 0.5
M3.5 × 0.6
M4 × 0.7
M5 × 0.8
M6 × 1
M8 × 1.25
M10 × 1.5
M12 × 1.75
DP
Point Diameter
Max
1.33
1.73
2.12
2.46
2.80
3.60
4.25
5.82
7.36
8.90
Min
1.21
1.57
1.93
2.24
2.55
3.28
3.85
5.30
6.71
8.11
La
Nominal Screw Length
Max
13
13
16
20
25
30
40
40
40
45
a Header points apply to these nominal lengths or shorter. The pointing of longer lengths may require
machining to the dimensions specified.
The edge of the point may be rounded and the end of point need not be flat nor perpendicular to the
axis of screw shank.
Threads: Threads for metric machine screws are coarse M profile threads, as given in
ANSI B1.13M (see page 1783), unless otherwise specified.
Length of Thread: The lengths of threads on metric machine screws are given in Table 1
for the applicable screw type, size, and length.
Diameter of Body: The body diameters of metric machine screws are within the limits
specified in the dimensional tables (Tables 3 through 4 and 6).
Designation: Metric machine screws are designated by the following data in the
sequence shown: Nominal size and thread pitch; nominal length; product name, including
head type and driving provision; header point if desired; material (including property
class, if steel); and protective finish, if required. For example:
M8 × 1.25 × 30 Slotted Pan Head Machine Screw, Class 4.8 Steel, Zinc Plated
M3.5 × 0.6 × 20 Type IA Cross Recessed Oval Countersunk Head Machine Screw,
Header Point, Brass
It is common ISO practice to omit the thread pitch from the product size designation
when screw threads are the metric coarse thread series, e.g., M10 stands for M10 × 1.5.
1602
Table 6. American National Standard Hex and Hex Flange Head Metric Machine Screws ANSI/ASME B18.6.7M-1985
Hex Head
M2 × 0.4
M2.5 × 0.45
M3 × 0.5
M3.5 × 0.6
M4 × 0.7
M5 × 0.8
M6 × 1
M8 × 1.25
M10 × 1.5
M12 × 1.75
M10 × 1.5b
Sa
Ea
Hex Width
Across Flats
Body Diameter
DA
K
R
Underhead Fillet
Hex Width
Across
Corners
Head
Height
Transition
Dia
Radius
Max
Min
Max
Min
Min
Max
Min
Max
Min
2.00
2.50
3.00
3.50
4.00
5.00
6.00
8.00
10.00
12.00
10.00
1.65
2.12
2.58
3.00
3.43
4.36
5.21
7.04
8.86
10.68
8.86
3.20
4.00
5.00
5.50
7.00
8.00
10.00
13.00
16.00
18.00
15.00
3.02
3.82
4.82
5.32
6.78
7.78
9.78
12.73
15.73
17.73
14.73
3.38
4.28
5.40
5.96
7.59
8.71
10.95
14.26
17.62
19.86
16.50
1.6
2.1
2.3
2.6
3.0
3.8
4.7
6.0
7.5
9.0
7.5
1.3
1.8
2.0
2.3
2.6
3.3
4.1
5.2
6.5
7.8
6.5
2.6
3.1
3.6
4.1
4.7
5.7
6.8
9.2
11.2
13.2
11.2
0.1
0.1
0.1
0.1
0.2
0.2
0.3
0.4
0.4
0.4
0.4
a Dimensions across flats and across corners of the head are measured at the point of maximum metal. Taper of sides of head (angle between one side and the axis) shall
not exceed 2° or 0.10 mm, whichever is greater, the specified width across flats being the large dimension.
b The M10 size screws having heads with 15 mm width across flats are not ISO Standard. Unless M10 size screws with 15 mm width across flats are specifically
ordered, M10 size screws with 16 mm width across flats shall be furnished.
DS
Nominal
Screw
Size and
Thread
Pitch
Table 6. (Continued) American National Standard Hex and Hex Flange Head Metric Machine Screws ANSI/ASME B18.6.7M-1985
Hex Flange Head
Max
Min
Max
Min
Hex Width
Across
Corners, Ea
Min
M2 × 0.4
M2.5 × 0.45
M3 × 0.5
M3.5 × 0.6
M4 × 0.7
M5 × 0.8
M6 × 1
M8 × 1.25
M10 × 1.5
M12 × 1.75
2.00
2.50
3.00
3.50
4.00
5.00
6.00
8.00
10.00
12.00
1.65
2.12
2.58
3.00
3.43
4.36
5.21
7.04
8.86
10.68
3.00
3.20
4.00
5.00
5.50
7.00
8.00
10.00
13.00
15.00
2.84
3.04
3.84
4.82
5.32
6.78
7.78
9.78
12.72
14.72
3.16
3.39
4.27
5.36
5.92
7.55
8.66
10.89
14.16
16.38
Hex Width Across Flats, Sa
Hex
Height, K1
Min,
Flange
Edge
Thickness,
Cb
Min
Flange
Top
Fillet
Radius, R1
Max
Max
Transition
Dia, DA
Min
Radius, R
1.3
1.6
1.9
2.4
2.8
3.5
4.2
5.6
7.0
8.4
0.3
0.3
0.4
0.5
0.6
0.7
1.0
1.2
1.4
1.8
0.1
0.2
0.2
0.2
0.2
0.3
0.4
0.5
0.6
0.7
2.6
3.1
3.6
4.1
4.7
5.7
6.8
9.2
11.2
13.2
0.1
0.1
0.1
0.1
0.2
0.2
0.3
0.4
0.4
0.4
Flange Diameter, DC
Max
Min
Overall
Head
Height, K
4.5
5.4
6.4
7.5
8.5
10.6
12.8
16.8
21.0
24.8
4.1
5.0
5.9
6.9
7.8
9.8
11.8
15.5
19.3
23.3
2.2
2.7
3.2
3.8
4.3
5.4
6.7
8.6
10.7
13.7
Underhead Fillet
1603
a Dimensions across flats and across corners of the head are measured at the point of maximum metal. Taper of sides of head (angle between one side and the axis) shall
not exceed 2° or 0.10 mm, whichever is greater, the specified width across flats being the large dimension.
b The contour of the edge at periphery of flange is optional provided the minimum flange thickness is maintained at the minimum flange diameter. The top surface of
flange may be straight or slightly rounded (convex) upward.
A slight rounding of all edges of the hexagon surfaces of indented hex heads is permissible provided the diameter of the bearing circle is not less than the equivalent
of 90 per cent of the specified minimum width across flats dimension.
Heads may be indented, trimmed, or fully upset at the option of the manufacturer.
Body
Diameter, DS
Nominal
Screw
Size and
Thread
Pitch
1604
MACHINE SCREWS
Table 7. Recommended Nominal Screw Lengths for Metric Machine Screws
Nominal
Screw
Length
2.5
3
4
5
6
8
10
13
16
20
25
30
35
40
45
50
55
60
65
70
80
90
Nominal Screw Size
M2
PH
A
A
A
A
A
A
A
A
A
M2.5
M3
PH
A
A
A
A
A
A
A
A
A
PH
A
A
A
A
A
A
A
A
A
M3.5
M4
PH
A
A
A
A
A
A
A
A
A
PH
A
A
A
A
A
A
A
A
A
A
M5
PH
A
A
A
A
A
A
A
A
A
A
A
M6
A
A
A
A
A
A
A
A
A
A
A
A
A
M8
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
M10
M12
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
H
H
H
H
H
H
H
H
H
H
H
H
H
H
1The nominal screw lengths included between the heavy lines are recommended for the respective
screw sizes and screw head styles as designated by the symbols.
A — Signifies screws of all head styles covered in this standard.
P — Signifies pan head screws.
H — Signifies hex and hex flange head screws.
Table 8. Clearance Holes for Metric Machine Screws
ANSI/ASME B18.6.7M-1985 Appendix
Nominal
Screw
Size
M2
M2.5
M3
M3.5
M4
M5
M6
M8
M10
M12
Close
Clearanceb
2.20
2.70
3.20
3.70
4.30
5.30
6.40
8.40
10.50
13.00
Basic Clearance Hole Diametera
Normal Clearance
(Preferred)b
2.40
2.90
3.40
3.90
4.50
5.50
6.60
9.00
11.00
13.50
Loose
Clearanceb
2.60
3.10
3.60
4.20
4.80
5.80
7.00
10.00
12.00
14.50
a The values given in this table are minimum limits. The recommended plus tolerances are as follows: for clearance hole diameters over 1.70 to and including 5.80 mm, plus 0.12, 0.20, and 0.30 mm
for close, normal, and loose clearances, respectively; for clearance hole diameters over 5.80 to 14.50
mm, plus 0.18, 0.30, and 0.45 mm for close, normal, and loose clearances, respectively.
b Normal clearance hole sizes are preferred. Close clearance hole sizes are for situations such as critical alignment of assembled components, wall thickness, or other limitations which necessitate the
use of a minimal hole. Countersinking or counterboring at the fastener entry side may be necessary for
the proper seating of the head. Loose clearance hole sizes are for applications where maximum adjustment capability between the components being assembled is necessary.
MACHINE SCREWS
1605
British Machine Screws.—Many of these classifications of fasteners are covered in British Standards B.S. 57:1951, “B.A. Screws, Bolts and Nuts”; BS 450:1958 (obsolescent),
“Machine Screws and Machine Screw Nuts (BSW and BSF Threads)”; B.S. 1981:1953,
“Unified Machine Screws and Machine Screw Nuts”; BS 2827:1957 (obsolescent):1957,
“Machine Screw Nuts, Pressed Type (B.A. and Whitworth Form Threads)”; B.S.
3155:1960, “American Machine Screws and Nuts in Sizes Below 1⁄4 inch Diameter”; and
BS 4183:1967 (obsolescent), “Machine Screws and Machine Screw Nuts, Metric Series.”
At a conference organized by the British Standards Institution in 1965 at which the major
sectors of British industry were represented, a policy statement was approved that urged
British firms to regard the traditional screw thread systems—Whitworth, B.A. and BSF—
as obsolescent, and to make the internationally-agreed ISO metric thread their first choice
(with ISO Unified thread as second choice) for all future designs. It is recognized that some
sections of British industry already using ISO inch (Unified) screw threads may find it necessary, for various reasons, to continue with their use for some time: Whitworth and B.A.
threads should, however, be superseded by ISO metric threads in preference to an intermediate change to ISO inch threads. Fasteners covered by B.S. 57, B.S. 450 and BS
2827:1957 (obsolescent) eventually would be superseded and replaced by fasteners specified by B.S. 4183.
British Standard Whitworth (BSW) and Fine (BSF) Machine Screws.—British Standard BS 450:1958 (obsolescent) covers machine screws and nuts with British Standard
Whit-worth and British Standard Fine threads. All the various heads in common use in
both slotted and recessed forms are covered. Head shapes are shown on page 1614 and
dimensions on page 1617. It is intended that this standard will eventually be superseded by
B.S. 4183, “Machine Screws and Machine Screw Nuts, Metric Series.”
British Standard Machine Screws and Machine Screw Nuts, Metric Series.—British
Standard BS 4183:1967 (obsolescent) gives dimensions and tolerances for: countersunk
head, raised countersunk head, and cheese head slotted head screws in a diameter range
from M1 (1 mm) to M20 (20 mm); pan head slotted head screws in a diameter range from
M2.5 (2.5 mm) to M10 (10 mm); countersunk head and raised countersunk head recessed
head screws in a diameter range from M2.5 (2.5 mm) to M12 (12 mm); pan head recessed
head screws in a diameter range from M2.5 (2.5 mm) to M10 (10 mm); and square and
hexagon machine screw nuts in a diameter range from M1.6 (1.6 mm) to M10 (10 mm).
Mechanical properties are also specified for steel, brass and aluminum alloy machine
screws and machine screw nuts in this standard.
Material: The materials from which the screws and nuts are manufactured have a tensile
strength not less than the following: steel, 40 kgf/mm2 (392 N/mm2); brass, 32 kgf/mm2
(314 N/mm2); and aluminum alloy, 32 kgf/mm2 (314 N/mm2). The unit, kgf/mm2 is in
accordance with ISO DR 911 and the unit in parentheses has the relationship, 1 kgf =
9.80665 Newtons. These minimum strengths are applicable to the finished products. Steel
machine screws conform to the requirements for strength grade designation 4.8. The
strength grade designation system for machine screws consists of two figures, the first is 1⁄10
of the minimum tensile strength in kgf/mm2, the second is 1⁄10 of the ratio between the yield
stress and the minimum tensile strength expressed as a percentage: 1⁄10 minimum tensile
yield stress
strength of 40 kgf/mm2 gives the symbol “4”; 1⁄10 ratio ------------------------------------------------------------ % = 1⁄10 ×
minimum tensile strength
32⁄ × 100⁄1 = “8”; giving the strength grade designation “4.8.” Multiplication of these two
40
figures gives the minimum yield stress in kgf/mm2.
Coating of Screws and Nuts: It is recommended that the coating comply with the appropriate part of BS 3382. “Electroplated Coatings on Threaded Components.”
1606
MACHINE SCREWS
Screw Threads: Screw threads are ISO metric coarse pitch series threads in accordance
with B.S. 3643. “ISO Metric Screw Threads,” Part 1, “Thread Data and Standard Thread
Series.” The external threads used for screws conform to tolerance Class 6g limits
(medium fit) as given in B.S. 3643, “ISO Metric Screw Threads,” Part 2, “Limits and Tolerances for Coarse Pitch Series Threads.” The internal threads used for nuts conform to tolerance Class 6H limits (medium fit) as given in B.S. 3643: Part 2.
Nominal Lengths of Screws: For countersunk head screws the nominal length is the distance from the upper surface of the head to the extreme end of the shank, including any
chamfer, radius, or cone point. For raised countersunk head screws the nominal length is
the distance from the upper surface of the head (excluding the raised portion) to the
extreme end of the shank, including any chamfer, radius, or cone point. For pan and cheese
head screws the nominal length is the distance from the underside of the head to the
extreme end of the shank, including any chamfer, radius, or cone point. Standard nominal
lengths and tolerances are given in Table 5.
Lengths of Thread on Screws: The length of thread is the distance from the end of the
screw (including any chamfer, radius, or cone point) to the leading face of a nut without
countersink which has been screwed as far as possible onto the screw by hand. The minimum thread length is shown in the following table:
Nominal
Thread Dia., da
M1
M1.2
(M1.4)
M1.6
M2
(M2.2)
M2.5
M3
(M3.5)
M4
Thread Length
b (Min.)
b
b
b
15
16
17
18
19
20
22
Nominal Thread
Dia., da
(M4.5)
M5
M6
M8
M10
M12
(M14)
M16
(M18)
M20
Thread Length
b (Min.)
24
25
28
34
40
46
52
58
64
70
a Items shown in parentheses are non-preferred.
b Threaded up to the head.
All dimensions are in millimeters.
Screws of nominal thread diameter M1, M1.2 and M1.4 and screws of larger diameters
that are too short for the above thread lengths are threaded as far as possible up to the head.
In these screws the length of unthreaded shank under the head does not exceed 11⁄2 pitches
for lengths up to twice the diameter and 2 pitches for longer lengths, and is defined as the
distance from the leading face of a nut that has been screwed as far as possible onto the
screw by hand to: 1) the junction of the basic major diameter and the countersunk portion
of the head on countersunk and raised countersunk heads; and 2) the underside of the
head on other types of heads.
Diameter of Unthreaded Shank on Screws: The diameter of the unthreaded portion of
the shank on screws is not greater than the basic major diameter of the screw thread and not
less than the minimum effective diameter of the screw thread. The diameter of the
unthreaded portion of shank is closely associated with the method of manufacture; it will
generally be nearer the major diameter of the thread for turned screws and nearer the effective diameter for those produced by cold heading.
Radius Under the Head of Screws: The radius under the head of pan and cheese head
screws runs smoothly into the face of the head and shank without any step or discontinuity.
A true radius is not essential providing that the curve is smooth and lies wholly within the
maximum radius. Any radius under the head of countersunk head screws runs smoothly
into the conical bearing surface of the head and the shank without any step or discontinuity.
The radius values given in Tables 1 and 2 are regarded as the maximum where the shank
diameter is equal to the major diameter of the thread and minimum where the shank diameter is approximately equal to the effective diameter of the thread.
Table 1. British Standard Slotted Countersunk Head Machine Screws—Metric Series BS 4183:1967 (obsolescent)
Nominal
Size
da
Head Diameter
D
Head Height
k
Thread
Length
b
Thread
Run-out
a
Flushness
Tolerancec
Min.
Max.
2pd
Max.
Max.
Min.
Max.
0.3d
Min.
0.2d
e
0.50
....
0.45
0.31
0.30
0.20
0.1
e
0.50
....
0.50
0.36
0.36
0.24
0.63
0.1
e
0.60
....
0.50
0.36
0.42
0.28
0.72
0.90
0.99
1.12
1.35
1.57
1.80
2.03
2.25
2.70
3.60
4.50
5.40
6.30
7.20
8.10
9.00
0.1
0.1
0.1
0.1
0.1
0.2
0.2
0.2
0.2
0.25
0.4
0.4
0.6
0.6
0.6
0.6
0.8
15.0
16.0
17.0
18.0
19.0
20.0
22.0
24.0
25.0
28.0
34.0
40.0
46.0
52.0
58.0
64.0
70.0
0.70
0.80
0.90
0.90
1.00
1.20
1.40
1.50
1.60
2.00
2.50
3.00
3.50
4.00
4.00
5.00
5.00
....
....
....
0.10
0.12
0.13
0.15
0.17
0.19
0.23
0.29
0.37
0.44
0.52
0.60
0.67
0.75
0.60
0.70
0.80
0.80
1.00
1.00
1.20
1.20
1.51
1.91
2.31
2.81
3.31
3.31
4.37
4.37
5.37
0.46
0.56
0.66
0.66
0.86
0.86
1.06
1.06
1.26
1.66
2.06
2.56
3.06
3.06
4.07
4.07
5.07
0.48
0.60
0.66
0.75
0.90
1.05
1.20
1.35
1.50
1.80
2.40
3.00
3.60
4.20
4.80
5.40
6.00
0.32
0.40
0.44
0.50
0.60
0.70
0.80
0.90
1.00
1.20
1.60
2.00
2.40
2.80
3.20
3.60
4.00
Radius
rb
Min.
1.75d
Max.
0.5d
Min.
0.45d
M1
2.00
1.75
0.50
0.45
0.1
M1.2
2.40
2.10
0.60
0.54
(M1.4)
2.80
2.45
0.70
M1.6
M2.0
(M2.2)
M2.5
M3
(M3.5)
M4
(M4.5)
M5
M6
M8
M10
M12
(M14)
M16
(M18)
M20
3.20
4.00
4.40
5.00
6.00
7.00
8.00
9.00
10.00
12.00
16.00
20.00
24.00
28.00
32.00
36.00
40.00
2.80
3.50
3.85
4.38
5.25
6.10
7.00
7.85
8.75
10.50
14.00
17.50
21.00
24.50
28.00
31.50
35.00
0.80
1.00
1.10
1.25
1.50
1.75
2.00
2.25
2.50
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
Slot Width
n
Slot Depth
t
MACHINE SCREWS
Max.
(Theor.
Sharp)
2d
a Nominal sizes shown in parentheses are non-preferred.
b See Radius Under the Head of Screws description in text.
c See Dimensions of 90-Degree Countersunk Head Screws description in text.
d See text following table in Lengths of Thread on Screws description in text.
e Threaded up to head.
1607
All dimensions are given in millimeters. For dimensional notation, see diagram on page 1610. Recessed head screws are also standard and are available. For dimensions see British Standard.
Head Diameter
D
Head Height
k
Thread
Length
b
Thread
Runout
a
Height
of
Raised
Portion
f
Head
Radius
R
Slot Width
n
1608
Table 2. British Standard Slotted Raised Countersunk Head Machine Screws—Metric Series BS 4183:1967 (obsolescent)
Slot Depth
t
Min.
1.75d
Max.
0.5d
Min.
0.45d
Min.
Max.
2pc
Nom.
0.25d
Nom.
Max.
Min.
Max.
0.5d
Min.
0.4d
M1
2.00
1.75
0.50
0.45
0.1
d
0.50
0.25
2.0
0.45
0.31
0.50
0.40
M1.2
2.40
2.10
0.60
0.54
0.1
d
0.50
0.30
2.5
0.50
0.36
0.60
0.48
(M1.4)
2.80
2.45
0.70
0.63
0.1
d
0.60
0.35
2.5
0.50
0.36
0.70
0.56
M1.6
3.20
2.80
0.80
0.72
0.1
15.0
0.70
0.40
3.0
0.60
0.46
0.80
0.64
M2.0
4.00
3.50
1.00
0.90
0.1
16.0
0.80
0.50
4.0
0.70
0.56
1.00
0.80
(M2.2)
4.40
3.85
1.10
0.99
0.1
17.0
0.90
0.55
4.0
0.80
0.66
1.10
0.88
M2.5
5.00
4.38
1.25
1.12
0.1
18.0
0.90
0.60
5.0
0.80
0.66
1.25
1.00
M3
6.00
5.25
1.50
1.35
0.1
19.0
1.00
0.75
6.0
1.00
0.86
1.50
1.20
(M3.5)
7.00
6.10
1.75
1.57
0.2
20.0
1.20
0.90
6.0
1.00
0.86
1.75
1.40
M4
8.00
7.00
2.00
1.80
0.2
22.0
1.40
1.00
8.0
1.20
1.06
2.00
1.60
(M4.5)
M5
9.00
7.85
2.25
2.03
0.2
24.0
1.50
1.10
8.0
1.20
1.06
2.25
1.80
10.00
8.75
2.50
2.25
0.2
25.0
1.60
1.25
10.0
1.51
1.26
2.50
2.00
M6
12.00
10.50
3.00
2.70
0.25
28.0
2.00
1.50
12.0
1.91
1.66
3.00
2.40
M8
16.00
14.00
4.00
3.60
0.4
34.0
2.50
2.00
16.0
2.31
2.06
4.00
3.20
M10
20.00
17.50
5.00
4.50
0.4
40.0
3.00
2.50
20.0
2.81
2.56
5.00
4.00
M12
24.00
21.00
6.00
5.40
0.6
46.0
3.50
3.00
25.0
3.31
3.06
6.00
4.80
(M14)
28.00
24.50
7.00
6.30
0.6
52.0
4.00
3.50
25.0
3.31
3.06
7.00
5.60
M16
32.00
28.00
8.00
7.20
0.6
58.0
4.00
4.00
32.0
4.37
4.07
8.00
6.40
(M18)
36.00
31.50
9.00
8.10
0.6
64.0
5.00
4.50
32.0
4.37
4.07
9.00
7.20
M20
40.00
35.00
10.00
9.00
0.8
70.0
5.00
5.00
40.0
5.37
5.07
10.00
8.00
b See Radius Under the Head of Screws description in text.
c See text following table in Lengths of Thread on Screws description in text.
d Threaded up to head.
All dimensions are given in millimeters. For dimensional notation see diagram on page 1610. Recessed head screws are also standard and available. For dimensions
see British Standard.
MACHINE SCREWS
Max.
(Theor.
Sharp)
2d
Radius
Under
Head
rb
Nominal
Size
da
MACHINE SCREWS
1609
Ends of Screws: When screws are made with rolled threads, the “lead” formed by the
thread rolling operation is normally regarded as providing the necessary chamfer and no
other machining is necessary. The ends of screws with cut threads are normally finished
with a chamfer conforming to the dimension in Fig. 1a through Fig. 1d. At the option of the
manufacturer, the ends of screws smaller than M6 (6-mm diameter) may be finished with a
radius approximately equal to 11⁄4 times the nominal diameter of the shank. When cone
point ends are required, they should have the dimensions given in Fig. 1a through Fig. 1d.
Nominal
Length
Nominal
Length
d
90
d
Cut Thread Chamfered End
Fig. 1a. Rolled Thread End
(Approximate Form as Rolled)
d
Radius
Approx.
1 1/ 4 d
Nominal
Length
Fig. 1c. Cut Thread Radiused End
(Permissible on Sizes Below M6 Dia.)
Fig. 1b. Chamfer to Extend to Slightly
Below the Minor Dia.
90
d
Nominal
Length
Fig. 1d. Cone Pointed End (Permissible on Cut or
Rolled Thread Screws, but Regarded as "Special")
Dimensions of 90-Degree Countersunk Head Screws: One of the appendices to this British Standard states that countersunk head screws should fit into the countersunk hole with
as great a degree of flushness as possible. To achieve this condition, it is necessary for the
dimensions of both the head of the screw and the countersunk hole to be controlled within
prescribed limits. The maximum or design size of the head is controlled by a theoretical
diameter to a sharp corner and the minimum head angle of 90 degrees. The minimum head
size is controlled by a minimum head diameter, the maximum head angle of 92 degrees and
a flushness tolerance (see Fig. 2). The edge of the head may be flat or rounded, as shown in
Fig. 3.
Fig. 2. Head Configuration
Fig. 3. Edge Configuration
1610
MACHINE SCREWS
British Standard Machine Screws and Machine Screw Nuts—Metric Series
l
l
k
a
r
b
90 +2 D D n
d
Edge May Be
Rounded or
Flat, But Not
Sharp Edges
t
Shank Dia. ≈
Effective
Dia.
Shank Dia. ≈
Major Dia.
Slotted Countersunk Head Machine Screws
l
f
l
k
a
r
90 +2 D D n
b
d
R
Edge May Be
Shank Dia. ≈
Rounded or
Shank Dia. ≈
Effective
Major Dia.
Flat, But Not
Dia.
Sharp Edges
Slotted Raised Countersunk Head Machine Screws
t
k
l
R
l
a
r
b
D n
d
t
0 TO 5
da
k
Shank Dia. ≈
Effective Dia.
Slotted Pan Head Machine Screws
l
R
l
a
r
b
D n
0 TO 5
Shank Dia. ≈
Major Dia.
d
t
da
Shank Dia. ≈
Effective Dia.
Slotted Cheese Head Machine Screws
;
d
s
d
;
Shank Dia. ≈
Major Dia.
e
m
s
e
Square Nut
Hexagon Nut
Machine Screw Nuts, Pressed Type, Square and Hexagon
m
For dimensions, see Tables 1 through 5.
MACHINE SCREWS
1611
Table 3. British Standard Slotted Pan Head Machine Screws—
Metric Series BS 4183:1967 (obsolescent)
Nominal
Size
da
M2.5
M3
(M3.5)
M4
(M4.5)
M5
M6
M8
M10
Head
Diameter
D
Head
Height
k
Head
Radius
R
Radius
Under
Head
r
Transition
Diameter
da
Max.
2d
Min.
Max.
0.6d
Min.
Max
0.4d
Min.
Max.
5.00
6.00
7.00
8.00
9.00
10.00
12.00
16.00
20.00
4.70
5.70
6.64
7.64
8.64
9.64
11.57
15.57
19.48
1.50
1.80
2.10
2.40
2.70
3.00
3.60
4.80
6.00
1.36
1.66
1.96
2.26
2.56
2.86
3.42
4.62
5.82
1.00
1.20
1.40
1.60
1.80
2.00
2.50
3.20
4.00
0.10
0.10
0.20
0.20
0.20
0.20
0.25
0.40
0.40
3.10
3.60
4.30
4.70
5.20
5.70
6.80
9.20
11.20
Nominal
Size
da
M2.5
M3
(M3.5)
M4
(M4.5)
M5
M6
M8
M10
Thread
Length
b
Thread
Run-out
a
Min.
Max.
2pb
Max.
Min.
Max.
0.6k
Min.
0.4k
18.00
19.00
20.00
22.00
24.00
25.00
28.00
34.00
40.00
0.90
1.00
1.20
1.40
1.50
1.60
2.00
2.50
3.00
0.80
1.00
1.00
1.20
1.20
1.51
1.91
2.31
2.81
0.66
0.86
0.86
1.06
1.06
1.26
1.66
2.06
2.56
0.90
1.08
1.26
1.44
1.62
1.80
2.16
2.88
3.60
0.60
0.72
0.84
0.96
1.08
1.20
1.44
1.92
2.40
Slot
Width
n
Slot
Depth
t
b See Lengths of Thread on Screws on page 1606.
All dimensions are in millimeters. For dimensional notation, see diagram on page 1610. Recessed
head screws are also standard and available. For dimensions, see British Standard.
Head
Diameter
D
Nominal
Size
da
Head
Height
k
Radius
rb
Transition
Diameter
da
Thread
Length
b
Thread
Run-out
a
Slot
Width
n
1612
Table 4. British Standard Slotted Cheese Head Machine Screws—Metric Series BS 4183:1967 (obsolescent)
Slot
Depth
t
Max.
Min.
Max.
Min.
Min.
Max.
Min.
Max. c
Max.
Min.
Max.
Min.
M1
2.00
1.75
0.70
0.56
0.10
1.30
b
0.50
0.45
0.31
0.44
0.30
M1.2
2.30
2.05
0.80
0.66
0.10
1.50
b
0.50
0.50
0.36
0.49
0.35
(M1.4)
2.60
2.35
0.90
0.76
0.10
1.70
b
0.60
0.50
0.36
0.60
0.40
M1.6
3.00
2.75
1.00
0.86
0.10
2.00
15.00
0.70
0.60
0.46
0.65
0.45
3.80
3.50
1.30
1.16
0.10
2.60
16.00
0.80
0.70
0.56
0.85
0.60
4.00
3.70
1.50
1.36
0.10
2.80
17.00
0.90
0.80
0.66
1.00
0.70
M2.5
4.50
4.20
1.60
1.46
0.10
3.10
18.00
0.90
0.80
0.66
1.00
0.70
M3
5.50
5.20
2.00
1.86
0.10
3.60
19.00
1.00
1.00
0.86
1.30
0.90
(M3.5)
6.00
5.70
2.40
2.26
0.10
4.10
20.00
1.20
1.00
0.86
1.40
1.00
M4
7.00
6.64
2.60
2.46
0.20
4.70
22.00
1.40
1.20
1.06
1.60
1.20
(M4.5)
8.00
7.64
3.10
2.92
0.20
5.20
24.00
1.50
1.20
1.06
1.80
1.40
M5
8.50
8.14
3.30
3.12
0.20
5.70
25.00
1.60
1.51
1.26
2.00
1.50
M6
10.00
9.64
3.90
3.72
0.25
6.80
28.00
2.00
1.91
1.66
2.30
1.80
M8
13.00
12.57
5.00
4.82
0.40
9.20
34.00
2.50
2.31
2.06
2.80
2.30
M10
16.00
15.57
6.00
5.82
0.40
11.20
40.00
3.00
2.81
2.56
3.20
2.70
M12
18.00
17.57
7.00
6.78
0.60
14.20
46.00
3.50
3.31
3.06
3.80
3.20
(M14)
21.00
20.48
8.00
7.78
0.60
16.20
52.00
4.00
3.31
3.06
4.20
3.60
M16
24.00
23.48
9.00
8.78
0.60
18.20
58.00
4.00
4.37
4.07
4.60
4.00
(M18)
27.00
26.48
10.00
9.78
0.60
20.20
64.00
5.00
4.37
4.07
5.10
4.50
M20
30.00
29.48
11.00
10.73
0.80
22.40
70.00
5.00
5.27
5.07
5.60
5.00
b Threaded up to head.
c See text following table in Lengths of Thread on Screws description in text.
All dimensions are given in millimeters. For dimensional notation, see diagram on page 1610.
General Dimensions: The general dimensions and tolerances for screws and nuts are given in the accompanying tables. Although slotted screw
dimensions are given, recessed head screws are also standard and available. Dimensions of recessed head screws are given in BS 4183:1967 (obsolescent).
MACHINE SCREWS
M2
(M2.2)
Table 5. British Standard Machine Screws and Nuts — Metric Series BS 4183:1967 (obsolescent)
Concentricity Tolerances
IT 13
IT 13
Countersunk
& Raised
Countersunk
Heads
Pan & Cheese
Heads
Nominal
Size
da
M1, M1.2, (M1.4)
M1.6
M2, (M2.2), M2.5, M3
(M3.5)
M4, (M4.5), M5
M6
M8
M10, M12
(M14)
M16, (M18), M20
Head to
Shank
Head to Shank and Slot to Head (IT 13)
Countersunk, Raised
Csk., and Pan Heads
Cheese Heads
0.14
0.18
0.18
0.22
0.22
0.27
0.27
0.33
0.33
0.39
0.14
0.14
0.18
0.18
0.22
0.22
0.27
0.27
0.33
0.33
All dimensions are given in millimeters. For dimensional notation, see diagram on page 1610.
Width Across
Flats s
Corners e
Min.
Square
3.02
4.5
3.82
5.7
4.32
6.4
4.82
7.1
5.32
7.8
5.82
8.5
6.78
9.9
7.78
11.3
9.78
14.1
12.73
18.4
16.73
24.0
Nominal
Size
da
M1.6
M2
(M2.2)
(M2.5)
M3
(M3.5)
M4
M5
M6
M8
M10
Max.
3.2
4.0
4.5
5.0
5.5
6.0
7.0
8.0
10.0
13.0
17.0
Nominal
Size
da
M1.6
M2
(M2.2)
M2.5
M3
(M3.5)
M4
M5
M6
M8
M10
M8
M10
Width
Across
Corners e
Hexagon
3.7
4.6
5.2
5.8
6.4
6.9
8.1
9.2
11.5
15.0
19.6
13.0
17.0
Thickness
m
Min
0.75
0.95
0.95
1.35
1.35
1.75
1.75
2.25
2.75
3.70
4.70
18.4
24.0
Max.
1.0
1.2
1.2
1.6
1.6
2.0
2.0
2.5
3.0
4.0
5.0
12.73
16.73
1613
a Nominal sizes and lengths shown in parentheses are non-preferred.
Dimensions of Machine Screw Nuts, Pressed Type,
Square and Hexagon
MACHINE SCREWS
Slot to
Head
Nominal Lengths and Tolerances on Length
for Machine Screws
Tolerance Nominal Lengtha Tolerance
±0.12
45
±0.50
±0.12
50
±0.060
±0.20
55
±0.60
±0.20
60
±0.60
±0.24
65
±0.60
±0.24
70
±0.60
±0.24
75
±0.60
±0.29
80
±0.60
±0.29
85
±0.70
±0.29
90
±0.70
±0.29
(95)
±0.70
±0.35
100
±0.70
±0.35
(105)
±0.70
±0.35
110
±0.70
±0.35
(115)
±0.70
±0.35
120
±0.70
±0.42
(125)
±0.70
±0.42
130
±0.80
±0.42
140
±0.80
±0.42
150
±0.80
±0.42
160
±0.80
±0.50
190
±0.925
±0.50
200
±0.925
Nominal Lengtha
1.5
2
2.5
3
4
5
6
(7)
8
(9)
10
(11)
12
14
16
(18)
20
(22)
25
(28)
30
(38)
40
1614
MACHINE SCREWS
British Unified Machine Screws and Nuts.—British Standard B.S. 1981:1953 covers
certain types of machine screws and machine screw nuts for which agreement has been
reached with the United States and Canada as to general dimensions for interchangeability.
These types are: countersunk, raised-countersunk, pan, and raised-cheese head screws
with slotted or recessed heads; small hexagon head screws; and precision and pressed nuts.
All have Unified threads. Head shapes are shown on page 1614 and dimensions are given
on page 1616.
Identification: As revised by Amendment No. 1 in February 1955, this standard now
requires that the above-mentioned screws and nuts that conform to this standard should
have a distinguishing feature applied to identify them as Unified. All recessed head screws
are to be identified as Unified by a groove in the form of four arcs of a circle in the upper
surface of the head. All hexagon head screws are to be identified as Unified by: 1) a circular recess in the upper surface of the head; 2) a continuous line of circles indented on one
or more of the flats of the hexagon and parallel to the screw axis; and 3) at least two contiguous circles indented on the upper surface of the head. All machine screw nuts of the
pressed type shall be identified as Unified by means of the application of a groove indented
in one face of the nut approximately midway between the major diameter of the thread and
flats of the square or hexagon. Slotted head screws shall be identified as Unified either by
a circular recess or by a circular platform or raised portion on the upper surface of the head.
Machine screw nuts of the precision type shall be identified as Unified by either a groove
indented on one face of the front approximately midway between the major diameter of the
thread and the flats of the hexagon or a continuous line of circles indented on one or more
of the flats of the hexagon and parallel to the nut axis.
;;
;;;;;;;;
;
;;
;;
;;
;
;;;;;;;;;;
Recessed and Hexagon Head Screws
Precision Type
Pressed Type
Hexagon Machine Screw Nuts
Slotted Head Screws
Identification Markings for British Standard Unified Machine Screws
British Standard Machine Screws and Nuts
ricc:1958 (obsolescent) and B.S. 1981:1953
80° Countersunk head screw (Unified)
90° Countersink head screw (BSW & BSF)
Round head screw (BSW & BSF)
MACHINE SCREWS
1615
British Standard Machine Screws and Nuts (Continued)
ricc:1958 (obsolescent) and B.S. 1981:1953
80° Raised countersunk head screw (Unified)
90° Raised countersunk head screw (BSW & BSF)
Mushroom head screw (BSW & BSF)
Pan head screw (Unified, BSW & BSF)
Hexagon head screw (Unified)
Cheese head screw (BSW & BSF)
Hexagon head screw (Unified) alternate design
Raised cheese head screw (Unified)
Hexagon machine screw nut (Unified)
*Countersinks to suit the screws should have a maximum angle of 80° (Unified) or 90° (BSF and
BSW) with a negative tolerance.
†Unified countersunk and raised countersunk head screws 2 inches long and under are threaded
right up to the head. Other Unified, BSW and BSF machine screws 2 inches long and under have an
unthread shank equal to twice the pitch. All Unified, BSW and BSF machine screws longer than 2
inches have a minimum thread length of 13⁄4 inches.
1616
MACHINE SCREWS
British Standard Unified Machine Screws and Nuts B.S. 1981:1953
Threads per Inch
UNC
UNF
Nom.Size
of Screw
Basic
Dia. D
4
6
8
10
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
0.112
0.138
0.164
0.190
0.250
0.3125
0.375
0.4375
0.500
0.625
0.750
40
32
32
24c
20
18
16
14
13
11
10
…
…
…
32
28
24
24
20
20
18
16
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
0.112
0.138
0.164
0.190
0.250
0.3125
0.375
0.4375
0.500
0.625
0.750
40
32
32
24c
20
18
16
14
13
11
10
…
…
…
32
28
24
24
20
20
18
16
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
0.112
0.138
0.164
0.190
0.250
0.3125
0.375
0.4375
0.500
0.625
0.750
40
32
32
24c
20
18
16
14
13
11
10
…
…
…
32
28
24
24
20
20
18
16
4
6
8
10
4
6
8
10
Dia. of Head A
Depth of Head B
Max.
Min.
Max.
Min.
80° Countersunk Head Screwsa,b
0.211
0.194
0.067
…
0.260
0.242
0.083
…
0.310
0.291
0.100
…
0.359
0.339
0.116
…
0.473
0.450
0.153
…
0.593
0.565
0.191
…
0.712
0.681
0.230
…
0.753
0.719
0.223
…
0.808
0.770
0.223
…
1.041
0.996
0.298
…
1.275
1.223
0.372
…
Pan Head Screwsb
0.219
0.205
0.068
0.058
0.270
0.256
0.082
0.072
0.322
0.306
0.096
0.085
0.373
0.357
0.110
0.099
0.492
0.473d
0.144
0.130
0.615
0.594
0.178
0.162
0.740
0.716
0.212
0.195
0.863
0.838
0.247
0.227
0.987
0.958
0.281
0.260
1.125
1.090
0.350
0.325
1.250
1.209
0.419
0.390
Raised Cheese-Head Screwsb
0.183
0.166
0.107
0.088
0.226
0.208
0.132
0.111
0.270
0.250
0.156
0.133
0.313
0.292
0.180
0.156
0.414
0.389
0.237
0.207
0.518
0.490
0.295
0.262
0.622
0.590
0.355
0.315
0.625
0.589
0.368
0.321
0.750
0.710
0.412
0.362
0.875
0.827
0.521
0.461
1.000
0.945
0.612
0.542
Width of Slot H
Max.
Min.
Depth of
Slot J
0.039
0.048
0.054
0.060
0.075
0.084
0.094
0.094
0.106
0.133
0.149
0.031
0.039
0.045
0.050
0.064
0.072
0.081
0.081
0.091
0.116
0.131
0.025
0.031
0.037
0.044
0.058
0.073
0.086
0.086
0.086
0.113
0.141
0.039
0.048
0.054
0.060
0.075
0.084
0.094
0.094
0.106
0.133
0.149
0.031
0.039
0.045
0.050
0.064
0.072
0.081
0.081
0.091
0.116
0.131
0.036
0.044
0.051
0.059
0.079
0.101
0.122
0.133
0.152
0.189
0.226
0.039
0.048
0.054
0.060
0.075
0.084
0.094
0.094
0.106
0.133
0.149
0.031
0.039
0.045
0.050
0.064
0.072
0.081
0.081
0.091
0.116
0.131
0.042
0.053
0.063
0.074
0.098
0.124
0.149
0.153
0.171
0.217
0.254
a All dimensions, except J, given for the No. 4 to 3⁄ -inch sizes, incl., also apply to all the 80° Raised
8
Countersunk Head Screws given in the Standard.
b Also available with recessed heads.
c Non-preferred.
d By arrangement may also be 0.468.
Nom.
Size
Basic
Dia.
D
Threads
per Inch
UNC
UNF
4
6
8
10
0.112
0.138
0.164
0.190
40
32
32
24c
4
6
8
10
0.112
0.138
0.164
0.190
40
32
32
24c
4
6
8
10
0.112
0.138
0.164
0.190
0.250
0.3125
0.375
40
32
32
24c
20
18
16
Width Across
Flats A
Corners C
Max.
Min.
Max.
H'd Depth B
Nut Thick. E
Max.
Min.
Wash. Face
Dia. F
Min.
Max.
Hexagon Head Screws
1⁄
4
5⁄
16
3⁄
8
…
0.1875
0.1835
0.216
0.060
…
0.2500
0.2450
0.289
0.080
…
0.2500
0.2450
0.289
0.110
32
0.3125
0.3075
0.361
0.120
Hexagon Machine Screw Nuts—Precision Type
…
0.1875
0.1835
0.216
0.098
…
0.2500
0.2450
0.269
0.114
…
0.3125
0.3075
0.361
0.130
…
0.3125
0.3075
0.361
0.130
Hexagon Machine Screw Nuts—Pressed Type
…
0.2500
0.2410
0.289
0.087
…
0.3125
0.3020
0.361
0.114
…
0.3438
0.3320
0.397
0.130
32
0.3750
0.3620
0.433
0.130
28
0.4375
0.4230
0.505
0.193
24
0.5625
0.5450
0.649
0.225
24
0.6250
0.6070
0.722
0.257
0.055
0.074
0.104
0.113
0.183
0.245
0.245
0.307
0.173
0.235
0.235
0.297
0.087
0.102
0.117
0.117
…
…
…
…
…
…
…
…
0.077
0.102
0.117
0.117
0.178
0.208
0.239
…
…
…
…
…
…
…
…
…
…
…
…
…
…
All dimensions in inches. See page 1614 for a pictorial representation and letter dimensions.
MACHINE SCREWS
1617
Depth of Head B
Max.
Min.
…
32c
28c
26
22
20
18
16
16c
14
12
0.219
0.328
0.383
0.438
0.547
0.656
0.766
0.875
0.984
1.094
1.312
0.201
0.307
0.360
0.412
0.518
0.624
0.729
0.835
0.941
1.046
1.257
0.056
0.084
0.098
0.113
0.141
0.169
0.197
0.225
0.253
0.281
0.338
…
…
…
…
…
…
…
…
…
…
…
0.039
0.050
0.055
0.061
0.071
0.082
0.093
0.104
0.115
0.126
0.148
0.032
0.042
0.046
0.051
0.061
0.072
0.082
0.092
0.103
0.113
0.134
0.027
0.041
0.048
0.055
0.069
0.083
0.097
0.111
0.125
0.138
0.166
40
24
…
20
18
16
14
12
12c
11
10
…
32c
28c
26
22
20
18
16
16c
14
12
0.219
0.328
0.383
0.438
0.547
0.656
0.766
0.875
0.984
1.094
1.312
0.206
0.312d
0.365
0.417
0.524
0.629
0.735
0.840
0.946
1.051
1.262
0.087
0.131
0.153
0.175
0.219
0.262
0.306
0.350
0.394
0.437
0.525
0.082
0.124
0.145
0.165
0.207
0.249
0.291
0.333
0.375
0.417
0.500
0.039
0.050
0.055
0.061
0.071
0.082
0.093
0.104
0.115
0.126
0.148
0.032
0.042
0.046
0.051
0.061
0.072
0.082
0.092
0.103
0.113
0.134
0.048
0.072
0.084
0.096
0.120
0.144
0.168
0.192
0.217
0.240
0.288
0.1250
0.1875
0.2188
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
40
24
…
20
18
16
14
12
12c
11
10
…
32c
28c
26
22
20
18
16
16c
14
12
0.245
0.373
0.425
0.492
0.615
0.740
0.863
0.987
1.031
1.125
1.250
0.231
0.375
0.407
0.473e
0.594
0.716
0.838
0.958
0.999
1.090
1.209
0.075
0.110
0.125
0.144
0.178
0.212
0.247
0.281
0.315
0.350
0.419
0.065
0.099
0.112
0.130
0.162
0.195
0.227
0.260
0.293
0.325
0.390
0.039
0.050
0.055
0.061
0.071
0.082
0.093
0.104
0.115
0.126
0.148
0.032
0.042
0.046
0.051
0.061
0.072
0.082
0.092
0.103
0.113
0.134
0.040
0.061
0.069
0.078
0.095
0.112
0.129
0.145
0.162
0.179
0.213
Cheese Head Screwsb
1⁄
8
3⁄
16
7⁄
32
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
0.1250
0.1875
0.2188
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
40
24
…
20
18
16
14
12
12c
11
10
…
32c
28c
26
22
20
18
16
16c
14
12
0.188
0.281
0.328
0.375
0.469
0.562
0.656
0.750
0.844
0.938
1.125
0.180
0.270
0.315
0.360
0.450
0.540
0.630
0.720
0.810
0.900
1.080
0.087
0.131
0.153
0.175
0.219
0.262
0.306
0.350
0.394
0.437
0.525
0.082
0.124
0.145
0.165
0.207
0.249
0.291
0.333
0.375
0.417
0.500
0.039
0.050
0.055
0.061
0.071
0.082
0.093
0.104
0.115
0.126
0.148
0.032
0.042
0.046
0.051
0.061
0.072
0.082
0.092
0.103
0.113
0.134
0.039
0.059
0.069
0.079
0.098
0.118
0.138
0.157
0.177
0.197
0.236
1⁄
8
3⁄
16
1⁄
4
5⁄
16
3⁄
8
0.1250
0.1875
0.2500
0.3125
0.3750
40
24
20
18
16
…
32c
26
22
20
0.289
0.448
0.573
0.698
0.823
0.272
0.425
0.546
0.666
0.787
0.078
0.118
0.150
0.183
0.215
0.066
0.103
0.133
0.162
0.191
0.043
0.060
0.075
0.084
0.094
0.035
0.050
0.064
0.072
0.081
0.040
0.061
0.079
0.096
0.112
Pan Head Screwsb
Round Head Screwsb
90° Countersunk Head Screwsab
Dia. of Head A
Max.
Min.
Mushroom
Head Screwsb
British Standard Whitworth (BSW) and Fine (BSF) Machine Screws
BS 450:1958 (obsolescent)
Threads per Inch
BSW
BSF
Nom. Size
of Screw
Basic
Dia. D
1⁄
8
3⁄
16
7⁄
32
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
1⁄
8
3⁄
16
7⁄
32
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
1⁄
8
3⁄
16
7⁄
32
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
0.1250
0.1875
0.2188
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
40
24
…
20
18
16
14
12
12c
11
10
0.1250
0.1875
0.2188
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
Width of Slot H
Max.
Min.
Depth
of Slot J
a All dimensions, except J, given for the 1⁄ -through 3⁄ -inch sizes also apply to all the 90° Raised
8
8
Countersunk Head Screw dimensions given in the Standard.
b These screws are also available with recessed heads; dimensions of recess are not given here but
may be found in the Standard.
c Non-preferred size; avoid use whenever possible.
d By arrangement may also be 0.309.
e By arrangement may also be 0.468.
All dimensions in inches.
See diagram on page 1614 for a pictorial representation of screws and letter dimensions.
1618
CAP SCREWS
CAP AND SET SCREWS
Slotted Head Cap Screws.—American National Standard ANSI/ASME B18.6.2-1998 is
intended to cover the complete general and dimensional data for the various styles of slotted head cap screws as well as square head and slotted headless set screws (see page 1625).
Reference should be made to this Standard for information or data not found in the following text or tables.
Length of Thread: The length of complete (full form) thread on cap screws is equal to
twice the basic screw diameter plus 0.250 in. with a plus tolerance of 0.188 in. or an amount
equal to 21⁄2 times the pitch of the thread, whichever is greater. Cap screws of lengths too
short to accommodate the minimum thread length have full form threads extending to
within a distance equal to 21⁄2 pitches (threads) of the head.
Designation: Slotted head cap screws are designated by the following data in the
sequence shown: Nominal size (fraction or decimal equivalent); threads per inch; screw
length (fraction or decimal equivalent); product name; material; and protective finish, if
required. Examples: 1⁄2-13 × 3 Slotted Round Head Cap Screw, SAE Grade 2 Steel, Zinc
Plated. .750-16 × 2.25 Slotted Flat Countersunk Head Cap Screw, Corrosion Resistant
Steel.
Table 1. American National Standard Slotted Flat Countersunk Head Cap Screws
ANSI/ASME B18.6.2-1998
Head Dia., A
Nominal
Sizea
or Basic
Screw Dia.
Body
Dia., E
Edge
Sharp
Edge
Rnd'd.
or Flat
Head
Hgt., H
Slot
Width, J
Slot
Depth, T
Filet
Rad., U
Max.
Min.
Max.
Min.
Ref.
Max.
Min.
Max.
Min.
Max.
1⁄
4
0.2500
.2500
.2450
.500
.452
.140
.075
.064
.068
.045
.100
5⁄
16
0.3125
.3125
.3070
.625
.567
.177
.084
.072
.086
.057
.125
3⁄
8
0.3750
.3750
.3690
.750
.682
.210
.094
.081
.103
.068
.150
7⁄
16
0.4375
.4375
.4310
.812
.736
.210
.094
.081
.103
.068
.175
1⁄
2
0.5000
.5000
.4930
.875
.791
.210
.106
.091
.103
.068
.200
9⁄
16
0.5625
.5625
.5550
1.000
.906
.244
.118
.102
.120
.080
.225
5⁄
8
0.6250
.6250
.6170
1.125
1.020
.281
.133
.116
.137
.091
.250
3⁄
4
0.7500
.7500
.7420
1.375
1.251
.352
.149
.131
.171
.115
.300
7⁄
8
0.8750
.8750
.8660
1.625
1.480
.423
.167
.147
.206
.138
.350
1
1.0000
1.0000
.9900
1.875
1.711
.494
.188
.166
.240
.162
.400
11⁄8
1.1250
1.1250
1.1140
2.062
1.880
.529
.196
.178
.257
.173
.450
11⁄4
1.2500
1.2500
1.2390
2.312
2.110
.600
.211
.193
.291
.197
.500
13⁄8
1.3750
1.3750
1.3630
2.562
2.340
.665
.226
.208
.326
.220
.550
11⁄2
1.5000
1.5000
1.4880
2.812
2.570
.742
.258
.240
.360
.244
.600
a When
specifying a nominal size in decimals, the zero preceding the decimal point is omitted as is
any zero in the fourth decimal place.
Threads: Threads are Unified Standard Class 2A; UNC, UNF and 8 UN Series or UNRC, UNRF,
and 8 UNR Series.
CAP SCREWS
1619
Table 2. American National Standard Slotted Round Head Cap Screws
Nom. Sizea
or Basic
Screw Diameter
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
Body
Diameter, E
Max.
Min.
Head
Diameter, A
Max.
Min.
Head
Height, H
Max.
Min.
Slot
Width, J
Max.
Min.
Slot
Depth, T
Max.
Min.
.2500
.3125
.3750
.4375
.5000
.5625
.6250
.7500
.437
.562
.625
.750
.812
.937
1.000
1.250
.191
.245
.273
.328
.354
.409
.437
.546
.075
.084
.094
.094
.106
.118
.133
.149
.117
.151
.168
.202
.218
.252
.270
.338
.2450
.3070
.3690
.4310
.4930
.5550
.6170
.7420
.418
.540
.603
.725
.786
.909
.970
1.215
.175
.226
.252
.302
.327
.378
.405
.507
.064
.072
.081
.081
.091
.102
.116
.131
.097
.126
.138
.167
.178
.207
.220
.278
a When specifying a nominal size in decimals, the zero preceding the decimal point is omitted as is
any zero in the fourth decimal place.
Fillet Radius, U: For fillet radius see foonote to table below.
Threads: Threads are Unified Standard Class 2A; UNC, UNF and 8 UN Series or UNRC, UNRF
and 8 UNR Series.
Table 3. American National Standard Slotted Fillister Head Cap Screws
Body
Dia.., E
Max.
Min.
Head
Dia.., A
Max.
Min.
Head
Side
Height, H
Max.
Min.
Total
Head
Height, O
Max. Min.
Slot
Width, J
Max. Min.
Slot
Depth, T
Max. Min.
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
.2500
.3125
.3750
.4375
.5000
.5625
.2450
.3070
.3690
.4310
.4930
.5550
.375
.437
.562
.625
.750
.812
.363
.424
.547
.608
.731
.792
.172
.203
.250
.297
.328
.375
.157
.186
.229
.274
.301
.346
.216
.253
.314
.368
.413
.467
.194
.230
.284
.336
.376
.427
.075
.084
.094
.094
.106
.118
.064
.072
.081
.081
.091
.102
.097
.115
.142
.168
.193
.213
.077
.090
.112
.133
.153
.168
0.6250
0.7500
0.8750
1.0000
.6250
.7500
.8750
1.0000
.6170
.7420
.8660
.9900
.875
1.000
1.125
1.312
.853
.976
1.098
1.282
.422
.500
.594
.656
.391
.466
.556
.612
.521
.612
.720
.803
.478
.566
.668
.743
.133
.149
.167
.188
.116
.131
.147
.166
.239
.283
.334
.371
.189
.223
.264
.291
Nom. Sizea
or Basic
Screw Dia.
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
7⁄
8
1
a When specifying nominal size in decimals, the zero preceding the decimal point is omitted as is any
zero in the fourth decimal place.
Fillet Radius, U: The fillet radius is as follows: For screw sizes 1⁄4 to 3⁄8 incl., .031 max. and .016
min.; 7⁄16 to 9⁄16, incl., .047 max., .016 min.; and for 5⁄8 to 1, incl., .062 max., .031 min.
Threads: Threads are Unified Standard Class 2A; UNC, UNF and 8 UN Series or UNRC, UNRF
and 8 UNR Series.
1620
CAP SCREWS
Table 4. American National Standard Hexagon and Spline Socket
Head Cap Screws ANSI/ASME B18.3-1998
Nominal
Size
0
1
2
3
4
5
6
8
10
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
7⁄
8
1
11⁄8
11⁄4
13⁄8
11⁄2
13⁄4
2
21⁄4
21⁄2
23⁄4
3
31⁄4
31⁄2
33⁄4
4
Body Diameter, D
Max
Min
0.0600
0.0568
0.0730
0.0695
0.0860
0.0822
0.0990
0.0949
0.1120
0.1075
0.1250
0.1202
0.1380
0.1329
0.1640
0.1585
0.1900
0.1840
0.2500
0.2435
0.3125
0.3053
0.3750
0.3678
0.4375
0.4294
0.5000
0.4919
0.6250
0.6163
0.7500
0.7406
0.8750
0.8647
1.0000
0.9886
1.1250
1.1086
1.2500
1.2336
1.3750
1.3568
1.5000
1.4818
1.7500
1.7295
2.0000
1.9780
2.2500
2.2280
2.5000
2.4762
2.7500
2.7262
3.0000
2.9762
3.2500
3.2262
3.5000
3.4762
3.7500
3.7262
4.0000
3.9762
Head
Diameter, A
Max
Min
0.096
0.091
0.118
0.112
0.140
0.134
0.161
0.154
0.183
0.176
0.205
0.198
0.226
0.218
0.270
0.262
0.312
0.303
0.375
0.365
0.469
0.457
0.562
0.550
0.656
0.642
0.750
0.735
0.938
0.921
1.125
1.107
1.312
1.293
1.500
1.479
1.688
1.665
1.875
1.852
2.062
2.038
2.250
2.224
2.625
2.597
3.000
2.970
3.375
3.344
3.750
3.717
4.125
4.090
4.500
4.464
4.875
4.837
5.250
5.211
5.625
5.584
6.000
5.958
Head
Height, H
Max
Min
0.060
0.057
0.073
0.070
0.086
0.083
0.099
0.095
0.112
0.108
0.125
0.121
0.138
0.134
0.164
0.159
0.190
0.185
0.250
0.244
0.312
0.306
0.375
0.368
0.438
0.430
0.500
0.492
0.625
0.616
0.750
0.740
0.875
0.864
1.000
0.988
1.125
1.111
1.250
1.236
1.375
1.360
1.500
1.485
1.750
1.734
2.000
1.983
2.250
2.232
2.500
2.481
2.750
2.730
3.000
2.979
3.250
3.228
3.500
3.478
3.750
3.727
4.000
3.976
Spline
Socketa
Size, M
0.060
0.072
0.096
0.096
0.111
0.111
0.133
0.168
0.183
0.216
0.291
0.372
0.454
0.454
0.595
0.620
0.698
0.790
…
…
…
…
…
…
…
…
…
…
…
…
…
…
Nom. Hex.
Socket
Size, J
0.050
1⁄
0.062
16
5⁄
0.078
64
5⁄
0.078
64
3⁄
0.094
32
3⁄
0.094
32
7⁄
0.109
64
9⁄
0.141
64
5⁄
0.156
32
3⁄
0.188
16
1⁄
0.250
4
5⁄
0.312
16
3⁄
0.375
8
3⁄
0.375
8
1⁄
0.500
2
5⁄
0.625
8
3⁄
0.750
4
3⁄
0.750
4
7⁄
0.875
8
7⁄
0.875
8
1
1.000
1
1.000
11⁄4
1.250
11⁄2
1.500
13⁄4
1.750
13⁄4
1.750
2
2.000
21⁄4
2.250
1
2 ⁄4
2.250
23⁄4
2.750
23⁄4
2.750
3
3.000
Fillet
Ext., F
Max
0.007
0.007
0.008
0.008
0.009
0.010
0.010
0.012
0.014
0.014
0.017
0.020
0.023
0.026
0.032
0.039
0.044
0.050
0.055
0.060
0.065
0.070
0.080
0.090
0.100
0.110
0.120
0.130
0.140
0.150
0.160
0.170
Key
Engagementa, T
0.025
0.031
0.038
0.044
0.051
0.057
0.064
0.077
0.090
0.120
0.151
0.182
0.213
0.245
0.307
0.370
0.432
0.495
0.557
0.620
0.682
0.745
0.870
0.995
1.120
1.245
1.370
1.495
1.620
1.745
1.870
1.995
a Key engagement depths are minimum. Spline socket sizes are nominal.
All dimensions in inches. The body length LB of the screw is the length of the unthreaded cylindrical portion of the shank. The length of thread, LT, is the distance from the extreme point to the last
complete (full form) thread. Standard length increments for screw diameters up to 1 inch are 1⁄16 inch
for lengths 1⁄8 through 1⁄4 inch, 1⁄8 inch for lengths 1⁄4 through 1 inch, 1⁄4 inch for lengths 1 through 3 1⁄2
inches, 1⁄2 inch for lengths 3 1⁄2 through 7 inches, 1 inch for lengths 7 through 10 inches and for diameters over 1 inch are 1⁄2 inch for lengths 1 through 7 inches, 1 inch for lengths 7 through 10 inches, and
2 inches for lengths over 10 inches.
Heads may be plain or knurled, and chamfered to an angle E of 30 to 45 degrees with the surface of
the flat. The thread conforms to the Unified Standard with radius root, Class 3A UNRC and UNRF
for screw sizes No. 0 through 1 inch inclusive, Class 2A UNRC and UNRF for over 1 inch through 1
1⁄ inches inclusive, and Class 2A UNRC for larger sizes. Socket dimensions are given in Table 11.
2
For details not shown, including materials, see ANSI/ASME B18.3-1998.
CAP SCREWS
1621
Table 5. Drill and Counterbore Sizes For Socket Head Cap Screws (1960 Series)
Nominal Drill Size
Nominal
Size
or Basic
Screw
Diameter
0
1
2
3
4
5
6
8
10
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
7⁄
8
1
11⁄4
11⁄2
13⁄4
2
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2500
0.3125
0.3750
0.4375
0.5000
0.6250
0.7500
0.8750
1.0000
1.2500
1.5000
1.7500
2.0000
Close Fitb
Number or
Fractional
Decimal
Size
Size
Normal Fitc
Number or
Fractional
Decimal
Size
Size
A
51
46
3⁄
32
36
1⁄
8
9⁄
64
23
15
5
17⁄
64
21⁄
64
25⁄
64
29⁄
64
33⁄
64
41⁄
64
49⁄
64
57⁄
64
1
1 ⁄64
9
1 ⁄32
117⁄32
125⁄32
21⁄32
0.067
0.081
0.094
0.106
0.125
0.141
0.154
0.180
0.206
0.266
0.328
0.391
0.453
0.516
0.641
0.766
0.891
1.016
1.281
1.531
1.781
2.031
49
43
36
31
29
23
18
10
2
9⁄
32
11⁄
32
13⁄
32
15⁄
32
17⁄
32
21⁄
32
25⁄
32
29⁄
32
1
1 ⁄32
5
1 ⁄16
19⁄16
113⁄16
21⁄16
0.073
0.089
0.106
0.120
0.136
0.154
0.170
0.194
0.221
0.281
0.344
0.406
0.469
0.531
0.656
0.781
0.906
1.031
1.312
1.562
1.812
2.062
Counterbore
Diameter
B
1⁄
8
5⁄
32
3⁄
16
7⁄
32
7⁄
32
1⁄
4
9⁄
32
5⁄
16
3⁄
8
7⁄
16
17⁄
32
5⁄
8
23⁄
32
13⁄
16
1
13⁄16
13⁄8
15⁄8
2
23⁄8
23⁄4
31⁄8
Countersink
Diametera
C
0.074
0.087
0.102
0.115
0.130
0.145
0.158
0.188
0.218
0.278
0.346
0.415
0.483
0.552
0.689
0.828
0.963
1.100
1.370
1.640
1.910
2.180
a Countersink: It is considered good practice to countersink or break the edges of holes which are
smaller than (D Max + 2F Max) in parts having a hardness which approaches, equals or exceeds the
screw hardness. If such holes are not countersunk, the heads of screws may not seat properly or the
sharp edges on holes may deform the fillets on screws thereby making them susceptible to fatigue in
applications involving dynamic loading. The countersink or corner relief, however, should not be
larger than is necessary to insure that the fillet on the screw is cleared.
b Close Fit: The close fit is normally limited to holes for those lengths of screws which are threaded
to the head in assemblies where only one screw is to be used or where two or more screws are to be used
and the mating holes are to be produced either at assembly or by matched and coordinated tooling.
c Normal Fit: The normal fit is intended for screws of relatively long length or for assemblies involving two or more screws where the mating holes are to be produced by conventional tolerancing methods. It provides for the maximum allowable eccentricity of the longest standard screws and for certain
variations in the parts to be fastened, such as: deviations in hole straightness, angularity between the
axis of the tapped hole and that of the hole for the shank, differences in center distances of the mating
holes, etc.
Source: Appendix to American National Standard ANSI/ASME B18.3-1998.
1622
CAP SCREWS
Table 6. American National Standard Hexagon and Spline Socket Flat Countersunk
Head Cap Screws ANSI/ASME B18.3-1998
Nominal
Size
0
1
2
3
4
5
6
8
10
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
7⁄
8
1
11⁄8
11⁄4
13⁄8
11⁄2
Body
Diameter
Max.
Min.
D
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2500
0.3125
0.3750
0.4375
0.5000
0.6250
0.7500
0.8750
1.0000
1.1250
1.2500
1.3750
1.5000
0.0568
0.0695
0.0822
0.0949
0.1075
0.1202
0.1329
0.1585
0.1840
0.2435
0.3053
0.3678
0.4294
0.4919
0.6163
0.7406
0.8647
0.9886
1.1086
1.2336
1.3568
1.4818
Head
Diameter
Theoretical
Sharp
Abs.
Max.
Min.
A
0.138
0.168
0.197
0.226
0.255
0.281
0.307
0.359
0.411
0.531
0.656
0.781
0.844
0.938
1.188
1.438
1.688
1.938
2.188
2.438
2.688
2.938
0.117
0.143
0.168
0.193
0.218
0.240
0.263
0.311
0.359
0.480
0.600
0.720
0.781
0.872
1.112
1.355
1.604
1.841
2.079
2.316
2.553
2.791
HeadHeight
Reference
H
Spline
Socket
Size
M
Hexagon
Socket
Size
Nom.
J
Key
Engagement
Min.
T
0.044
0.054
0.064
0.073
0.083
0.090
0.097
0.112
0.127
0.161
0.198
0.234
0.234
0.251
0.324
0.396
0.468
0.540
0.611
0.683
0.755
0.827
0.048
0.060
0.060
0.072
0.072
0.096
0.096
0.111
0.145
0.183
0.216
0.251
0.291
0.372
0.454
0.454
…
…
…
…
…
…
0.035
0.050
0.050
1⁄
16
1⁄
16
5⁄
64
5⁄
64
3⁄
32
1⁄
8
5⁄
32
3⁄
16
7⁄
32
1⁄
4
5⁄
16
3⁄
8
1⁄
2
9⁄
16
5⁄
8
3⁄
4
7⁄
8
7⁄
8
1
0.025
0.031
0.038
0.044
0.055
0.061
0.066
0.076
0.087
0.111
0.135
0.159
0.159
0.172
0.220
0.220
0.248
0.297
0.325
0.358
0.402
0.435
The body of the screw is the unthreaded cylindrical portion of the shank where not threaded to the
head; the shank being the portion of the screw from the point of juncture of the conical bearing surface and the body to the flat of the point. The length of thread LT is the distance measured from the
extreme point to the last complete (full form) thread.
Standard length increments of No. 0 through 1-inch sizes are as follows: 1⁄16 inch for nominal screw
lengths of 1⁄8 through 1⁄4 inch; 1⁄8 inch for lengths of 1⁄4 through 1 inch; 1⁄4 inch for lengths of 1 inch
through 3 1⁄2 inches; 1⁄2 inch for lengths of 3 1⁄2 through 7 inches; and 1 inch for lengths of 7 through 10
inches, incl. For screw sizes over 1 inch, length increments are: 1⁄2 inch for nominal screw lengths of
1 inch through 7 inches; 1 inch for lengths of 7 through 10 inches; and 2 inches for lengths over 10
inches.
Threads shall be Unified external threads with radius root; Class 3A UNRC and UNRF series for
sizes No. 0 through 1 inch and Class 2A UNRC and UNRF series for sizes over 1 inch to 1 1⁄2 inches,
incl.
For manufacturing details not shown, including materials, see American National Standard
ANSI/ASME B18.3-1998 Socket dimensions are given in Table 11.
CAP SCREWS
1623
Table 7. American National Standard Hexagon Socket and Spline
Socket Button Head Cap Screws ANSI/ASME B18.3-1998
Screw
Diameter
Nominal
Size
Basic
Head
Diameter
Max.
D
Min.
Head
Height
Max.
A
Min.
H
Head
Side
Height
Spline
Socket
Sizea
Hexagon
Socket
Sizea
Standard
Length
Ref.
Nom.
Nom.
Max.
S
M
J
L
0
0.0600
0.114
0.104
0.032
0.026
0.010
0.048
0.035
1⁄
2
1
0.0730
0.139
0.129
0.039
0.033
0.010
0.060
0.050
1⁄
2
2
0.0860
0.164
0.154
0.046
0.038
0.010
0.060
0.050
1⁄
2
3
0.0990
0.188
0.176
0.052
0.044
0.010
0.072
1⁄
16
1⁄
2
4
0.1120
0.213
0.201
0.059
0.051
0.015
0.072
1⁄
16
1⁄
2
5
0.1250
0.238
0.226
0.066
0.058
0.015
0.096
5⁄
64
1⁄
2
6
0.1380
0.262
0.250
0.073
0.063
0.015
0.096
5⁄
64
5⁄
8
8
0.1640
0.312
0.298
0.087
0.077
0.015
0.111
3⁄
32
10
0.1900
0.361
0.347
0.101
0.091
0.020
0.145
1⁄
8
1
3⁄
4
1⁄
4
0.2500
0.437
0.419
0.132
0.122
0.031
0.183
5⁄
32
1
5⁄
16
0.3125
0.547
0.527
0.166
0.152
0.031
0.216
3⁄
16
1
3⁄
8
0.3750
0.656
0.636
0.199
0.185
0.031
0.251
7⁄
32
11⁄4
1⁄
2
0.5000
0.875
0.851
0.265
0.245
0.046
0.372
5⁄
16
2
5⁄
8
0.6250
1.000
0.970
0.331
0.311
0.062
0.454
3⁄
8
2
a Socket dimensions are given in Table 11.
These cap screws have been designed and recommended for light fastening applications. They are
not suggested for use in critical high-strength applications where socket head cap screws should normally be used.
Standard length increments for socket button head cap screws are as follows: 1⁄16 inch for nominal
screw lengths of 1⁄8 through 1⁄4 inch, 1⁄8 inch for nominal screw lengths of 1⁄4 through 1 inch, and 1⁄4 inch
for nominal screw lengths of 1 inch through 2 inches. Tolerances on lengths are −0.03 inch for
lengths up to 1 inch inclusive. For lengths from 1 through 2 inches, inclusive, length tolerances are −
0.04 inch.
The thread conforms to the Unified standard, Class 3A, with radius root, UNRC and UNRF.
To prevent interference, American National Standard ANSI/ASME B18.3.4M-1986 gives metric
dimensional and general requirements for a lower head profile hexagon socket button head cap
screw. Because of its design, wrenchability and other design factors are reduced; therefore,
B18.3.4M should be reviewed carefully. Available only in metric sizes and with metric threads.
For manufacturing details, including materials, not shown, see American National Standard
ANSI/ASME B18.3-1998
1624
CAP SCREWS
Table 8. American National Standard Hexagon Socket Head Shoulder Screws
Nominal
Size
1⁄
4
5⁄
16
3⁄
8
1⁄
2
5⁄
8
3⁄
4
1
11⁄4
11⁄2
13⁄4
2
Shoulder
Diameter
Max.
Min.
D
0.2480
0.3105
0.3730
0.4980
0.6230
0.7480
0.9980
1.2480
1.4980
1.7480
1.9980
0.2460
0.3085
0.3710
0.4960
0.6210
0.7460
0.9960
1.2460
1.4960
1.7460
1.9960
Thread Neck
Diameter
Nominal
Size
Max.
Min.
G
Head
Diameter
Max.
Min.
A
Head
Height
Max.
Min.
H
Head
Side
Height
Min.
S
Nominal
Thread
Size
D1
Thread
Length
E
0.375
0.438
0.562
0.750
0.875
1.000
1.312
1.750
2.125
2.375
2.750
0.357
0.419
0.543
0.729
0.853
0.977
1.287
1.723
2.095
2.345
2.720
0.188
0.219
0.250
0.312
0.375
0.500
0.625
0.750
1.000
1.125
1.250
0.157
0.183
0.209
0.262
0.315
0.421
0.527
0.633
0.842
0.948
1.054
10–24
1⁄ -20
4
5⁄ -18
16
3⁄ -16
8
1⁄ -13
2
5⁄ -11
8
3⁄ -10
4
7⁄ -9
8
11⁄8-7
11⁄4-7
11⁄2-6
0.375
0.438
0.500
0.625
0.750
0.875
1.000
1.125
1.500
1.750
2.000
Thread
Neck
Width
Shoulder
Neck
Dia.
Shoulder
Neck
Width
Max.
Min.
Max.
I
K
F
0.177
0.209
0.240
0.302
0.365
0.490
0.610
0.735
0.980
1.105
1.230
Thread Neck
Fillet
Max.
Min.
N
Head Fillet
Extension
Above D
Hexagon
Socket
Size
Max.
Nom.
M
J
1⁄
4
0.142
0.133
0.083
0.227
0.093
0.023
0.017
0.014
1⁄
8
5⁄
16
0.193
0.182
0.100
0.289
0.093
0.028
0.022
0.017
5⁄
32
3⁄
8
0.249
0.237
0.111
0.352
0.093
0.031
0.025
0.020
3⁄
16
1⁄
2
0.304
0.291
0.125
0.477
0.093
0.035
0.029
0.026
1⁄
4
5⁄
8
0.414
0.397
0.154
0.602
0.093
0.042
0.036
0.032
5⁄
16
3⁄
4
0.521
0.502
0.182
0.727
0.093
0.051
0.045
0.039
3⁄
8
1
0.638
0.616
0.200
0.977
0.125
0.055
0.049
0.050
1⁄
2
11⁄4
0.750
0.726
0.222
1.227
0.125
0.062
0.056
0.060
5⁄
8
11⁄2
0.964
0.934
0.286
1.478
0.125
0.072
0.066
0.070
13⁄4
1.089
1.059
0.286
1.728
0.125
0.072
0.066
0.080
1
2
1.307
1.277
0.333
1.978
0.125
0.102
0.096
0.090
11⁄4
7⁄
8
All dimensions are in inches. The shoulder is the enlarged, unthreaded portion of the screw. Standard length increments for shoulder screws are: 1⁄8 inch for nominal screw lengths of 1⁄4 through 3⁄4
inch; 1⁄4 inch for lengths above 3⁄4 through 5 inches; and 1⁄2 inch for lengths over 5 inches. The thread
conforms to the Unified Standard Class 3A, UNC. Hexagon socket sizes for the respective shoulder
screw sizes are the same as for set screws of the same nominal size (see Table 7) except for shoulder
screw size 1 inch, socket size is 1⁄2 inch, for screw size 1 1⁄2 inches, socket size is 7⁄8 inch, and for screw
size 2 inches, socket size is 1 1⁄4 inches. For details not shown, including materials, see ANSI/ASME
B18.3-1998.
SET SCREWS
1625
Table 9. American National Standard Slotted Headless Set Screws
FLAT POINT
DOG POINT HALF DOG POINT
CUP POINT
Nominal Sizea
or Basic
Screw
Diameter
0
1
2
3
4
5
6
8
10
12
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
OVAL POINT
Slot
Width, J
Slot
Depth, T
Cup and
Flat Point
Dia., C
CONE POINT
Dog
Point
Dia., P
Point Length
Dog, Q
Half
Dog, Q1
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
.014
.016
.018
.020
.024
.026
.028
.032
.035
.042
.049
.010
.012
.014
.016
.018
.020
.022
.026
.029
.035
.041
.020
.020
.025
.028
.031
.036
.040
.046
.053
.061
.068
.016
.016
.019
.022
.025
.026
.030
.036
.043
.051
.058
.033
.040
.047
.054
.061
.067
.074
.087
.102
.115
.132
.027
.033
.039
.045
.051
.057
.064
.076
.088
.101
.118
.040
.049
.057
.066
.075
.083
.092
.109
.127
.144
.156
.037
.045
.053
.062
.070
.078
.087
.103
.120
.137
.149
.032
.040
.046
.052
.058
.063
.073
.083
.095
.115
.130
.028
.036
.042
.048
.054
.057
.067
.077
.085
.105
.120
.017
.021
.024
.027
.030
.033
.038
.043
.050
.060
.068
.013
.017
.020
.023
.026
.027
.032
.037
.040
.050
.058
0.3125
.055
.047
.083
.073
.172
.156
.203
.195
.161
.151
.083
.073
0.3750
.068
.060
.099
.089
.212
.194
.250
.241
.193
.183
.099
.089
0.4375
.076
.068
.114
.104
.252
.232
.297
.287
.224
.214
.114
.104
0.5000
.086
.076
.130
.120
.291
.270
.344
.334
.255
.245
.130
.120
0.5625
.096
.086
.146
.136
.332
.309
.391
.379
.287
.275
.146
.134
0.6250
.107
.097
.161
.151
.371
.347
.469
.456
.321
.305
.164
.148
0.7500
.134
.124
.193
.183
.450
.425
.562
.549
.383
.367
.196
.180
a When
specifying a nominal size in decimals a zero preceding the decimal point or any zero in the
fourth decimal place is omitted.
Crown Radius, I: The crown radius has the same value as the basic screw diameter to three decimal
places.
Oval Point Radius, R: Values of the oval point radius according to nominal screw size are: For a
screw size of 0, a radius of .045; 1, .055; 2, .064; 3, .074; 4, .084; 5, .094; 6, .104; 8, .123; 10, .142; 12,
.162; 1⁄4, .188; 5⁄16, .234; 3⁄8, .281; 7⁄16, .328; 1⁄2, .375; 9⁄16, .422; 5⁄8, .469; and for 3⁄4, .562.
Cone Point Angle, Y: The cone point angle is 90° ± 2° for the following nominal lengths, or longer,
shown according to screw size: For nominal size 0, a length of 5⁄64; 1, 3⁄32; 2, 7⁄64; 3, 1⁄8; 4, 5⁄32; 5, 3⁄16; 6, 3⁄16;
8, 1⁄4; 10, 1⁄4; 12, 5⁄16; 1⁄4, 5⁄16; 5⁄16, 3⁄8; 3⁄8, 7⁄16; 7⁄16, 1⁄2; 1⁄2, 9⁄16; 9⁄16, 5⁄8; 5⁄8, 3⁄4; and for 3⁄4, 7⁄8. For shorter screws, the
cone point angle is 118° ± 2°.
Point Angle X: The point angle is 45°, + 5°, − 0°, for screws of nominal lengths, or longer, as given
just above for cone point angle, and 30°, min. for shorter screws.
Threads: are Unified Standard Class 2A; UNC and UNF Series or UNRC and UNRF Series.
1626
SET SCREWS
Table 10. American National Standard Hexagon and Spline Socket Set Screw
Optional Cup Points ANSI/ASME B18.3-1998
TYPE A
TYPE B
TYPE C
TYPE D
* This diameter may be counterbored.
TYPE E
TYPE F
Point Dia.
Nom.
Size
Max.
Min.
Max.
C
0
1
2
3
4
5
6
8
10
TYPE G
Point Dia.
Min.
Point Dia.
Max.
C1
Point Length
Min.
Max.
C2
Min.
S
1⁄
4
0.033
0.040
0.047
0.054
0.061
0.067
0.074
0.087
0.102
0.132
0.027
0.033
0.039
0.045
0.051
0.057
0.064
0.076
0.088
0.118
0.032
0.038
0.043
0.050
0.056
0.062
0.069
0.082
0.095
0.125
0.027
0.033
0.038
0.045
0.051
0.056
0.062
0.074
0.086
0.114
0.027
0.035
0.043
0.051
0.059
0.068
0.074
0.090
0.101
0.156
0.022
0.030
0.038
0.046
0.054
0.063
0.068
0.084
0.095
0.150
0.007
0.008
0.010
0.011
0.013
0.014
0.017
0.021
0.024
0.027
0.004
0.005
0.007
0.007
0.008
0.009
0.012
0.016
0.019
0.022
5⁄
16
0.172
0.156
0.156
0.144
0.190
0.185
0.038
0.033
3⁄
8
0.212
0.194
0.187
0.174
0.241
0.236
0.041
0.036
7⁄
16
0.252
0.232
0.218
0.204
0.286
0.281
0.047
0.042
1⁄
2
0.291
0.270
0.250
0.235
0.333
0.328
0.054
0.049
5⁄
8
0.371
0.347
0.312
0.295
0.425
0.420
0.067
0.062
3⁄
4
0.450
0.425
0.375
0.357
0.523
0.518
0.081
0.076
7⁄
8
1
11⁄8
0.530
0.609
0.689
0.502
0.579
0.655
0.437
0.500
0.562
0.418
0.480
0.542
…
…
…
…
…
…
…
…
…
…
…
…
11⁄4
0.767
0.733
0.625
0.605
…
…
…
…
13⁄8
0.848
0.808
0.687
0.667
…
…
…
…
11⁄2
0.926
0.886
0.750
0.730
…
…
…
…
13⁄4
1.086
1.244
1.039
1.193
0.875
1.000
0.855
0.980
…
…
…
…
…
…
…
…
2
The cup point types shown are those available from various manufacturers.
SET SCREWS
1627
Table 11. American National Standard Hexagon and Spline Sockets
BROACHED SOCKET
Nominal
Socket
Size
0.028
0.035
0.050
1⁄
16
5⁄
64
3⁄
32
7⁄
64
1⁄
8
Socket
Width
Across Flats
Max.
Min.
J
0.0285
0.0355
0.0510
0.0635
0.0791
0.0952
0.1111
0.1270
0.0280
0.0350
0.0500
0.0625
0.0781
0.0937
0.1094
0.1250
Nominal
Socket
Size
9⁄
64
5⁄
32
3⁄
16
7⁄
32
1⁄
4
5⁄
16
3⁄
8
…
HEXAGON SOCKETS
Socket
Socket
Width
Width
Across Flats
Across Flats
Nominal
Max.
Min.
Max.
Min.
Socket
J
J
Size
0.1426
0.1587
0.1900
0.2217
0.2530
0.3160
0.3790
…
0.1406
0.1562
0.1875
0.2187
0.2500
0.3125
0.3750
…
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
7⁄
8
0.4420
0.5050
0.5680
0.6310
0.7570
0.8850
1.0200
…
1
…
0.4375
0.5000
0.5625
0.6250
0.7500
0.8750
1.0000
…
Nominal
Socket
Size
11⁄4
11⁄2
13⁄4
2
21⁄4
23⁄4
3
…
Socket
Width
Across Flats
Max.
Min.
J
1.2750
1.5300
1.7850
2.0400
2.2950
2.8050
3.0600
…
1.2500
1.5000
1.7500
2.0000
2.2500
2.7500
3.0000
…
SPLINE SOCKETS
Nominal
Socket
Size
Number
of
Teeth
0.033
0.048
0.060
0.072
0.096
0.111
0.133
0.145
0.168
0.183
0.216
0.251
0.291
0.372
0.454
0.595
0.620
0.698
0.790
4
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
Socket Major
Diameter
Max.
Min.
M
0.0350
0.050
0.062
0.074
0.098
0.115
0.137
0.149
0.173
0.188
0.221
0.256
0.298
0.380
0.463
0.604
0.631
0.709
0.801
0.0340
0.049
0.061
0.073
0.097
0.113
0.135
0.147
0.171
0.186
0.219
0.254
0.296
0.377
0.460
0.601
0.627
0.705
0.797
Socket Minor
Diameter
Min.
N
Max.
0.0260
0.041
0.051
0.064
0.082
0.098
0.118
0.128
0.150
0.163
0.190
0.221
0.254
0.319
0.386
0.509
0.535
0.604
0.685
0.0255
0.040
0.050
0.063
0.080
0.096
0.116
0.126
0.147
0.161
0.188
0.219
0.252
0.316
0.383
0.506
0.531
0.600
0.681
Width of
Tooth
Max.
Min.
P
0.0120
0.011
0.014
0.016
0.022
0.025
0.030
0.032
0.036
0.039
0.050
0.060
0.068
0.092
0.112
0.138
0.149
0.168
0.189
0.0115
0.010
0.013
0.015
0.021
0.023
0.028
0.030
0.033
0.037
0.048
0.058
0.066
0.089
0.109
0.134
0.145
0.164
0.185
* Socket depths, T, for various screw types are given in the standard but are not shown here.
Where sockets are chamfered, the depth of chamfer shall not exceed 10 per cent of the nominal
socket size for sizes up to and including 1⁄16 inch for hexagon sockets and 0.060 for spline sockets, and
7.5 per cent for larger sizes.
1628
SET SCREWS
Table 12. American National Standard Square Head Set Screws
FLAT POINT
DOG POINT HALF DOG POINT
CUP POINT
Nominal
Size*
or Basic
Screw
Diameter
OVAL POINT
Cup and
Flat
Point
Diams., C
CONE POINT
Point Length
Dog and
Half Dog
Point
Diams., P
Dog, Q
Half Dog, Q1
Oval
Point
Rad., R
Max.
Min
Max.
Max.
Min.
Max.
Min.
+.031
−.000
0.1900
.102
.088
.127
.120
.095
.085
.050
.040
.142
1⁄
4
0.2500
.132
.118
.156
.149
.130
.120
.068
.058
.188
5⁄
16
0.3125
.172
.156
.203
.195
.161
.151
.083
.073
.234
3⁄
8
0.3750
.212
.194
.250
.241
.193
.183
.099
.089
.281
7⁄
16
0.4375
.252
.232
.297
.287
.224
.214
.114
.104
.328
1⁄
2
0.500
.291
.270
.344
.334
.255
.245
.130
.120
.375
9⁄
16
0.5625
.332
.309
.391
.379
.287
.275
.146
.134
.422
5⁄
8
0.6250
.371
.347
.469
.456
.321
.305
.164
.148
.469
3⁄
4
0.7500
.450
.425
.562
.549
.383
.367
.196
.180
.562
7⁄
8
0.8750
.530
.502
.656
.642
.446
.430
.227
.211
.656
1
1.0000
.609
.579
.750
.734
.510
.490
.260
.240
.750
11⁄8
1.1250
.689
.655
.844
.826
.572
.552
.291
.271
.844
11⁄4
1.2500
.767
.733
.938
.920
.635
.615
.323
.303
.938
13⁄8
1.3750
.848
.808
1.031
1.011
.698
.678
.354
.334
1.031
11⁄2
1.5000
.926
.886
1.125
1.105
.760
.740
.385
.365
1.125
10
Min.
*Threads: Threads are Unified Standard Class 2A; UNC, UNF and 8 UN Series or UNRC, UNRF
and 8 UNR Series.
Length of Thread: Square head set screws have complete (full form) threads extending over that
portion of the screw length which is not affected by the point. For the respective constructions,
threads extend into the neck relief, to the conical underside of head, or to within one thread (as measured with a thread ring gage) from the flat underside of the head. Threads through angular or
crowned portions of points have fully formed roots with partial crests.
* When specifying a nominal size in decimals, the zero preceding the decimal point is omitted as is any
zero in the fourth decimal place.
SET SCREWS
1629
Table 13. American National Standard Square Head Set Screws
OPTIONAL HEAD CONSTRUCTIONS
Nominal
Size or Basic
Screw Diameter
Width Across Width Across Head Height,
Flats,F
Corners,G
H
Neck Relief
Diameter, K
Neck
Relief
Fillet
Rad.,S
Neck
Relief
Width, U
Head
Rad.,,W
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
10
0.1900
.188
.180
.265
.247
.148
.134
.145
.140
.027
.083
0.48
1⁄
4
0.2500
.250
.241
.354
.331
.196
.178
.185
.170
.032
.100
0.62
5⁄
16
0.3125
.312
.302
.442
.415
.245
.224
.240
.225
.036
.111
0.78
3⁄
8
0.3750
.375
.362
.530
.497
.293
.270
.294
.279
.041
.125
0.94
7⁄
16
0.4375
.438
.423
.619
.581
.341
.315
.345
.330
.046
.143
1.09
1⁄
2
0.5000
.500
.484
.707
.665
.389
.361
.400
.385
.050
.154
1.25
9⁄
16
0.5625
.562
.545
.795
.748
.437
.407
.454
.439
.054
.167
1.41
5⁄
8
0.6250
.625
.606
.884
.833
.485
.452
.507
.492
.059
.182
1.56
3⁄
4
0.7500
.750
.729 1.060 1.001
.582
.544
.620
.605
.065
.200
1.88
7⁄
8
0.8750
.875
.852 1.237 1.170
.678
.635
.731
.716
.072
.222
2.19
1
1.0000
1.000
.974 1.414 1.337
.774
.726
.838
.823
.081
.250
2.50
11⁄8
1.1250
1.125 1.096 1.591 1.505
.870
.817
.939
.914
.092
.283
2.81
11⁄4
1.2500
1.250 1.219 1.768 1.674
.966
.908 1.064 1.039
.092
.283
3.12
13⁄8
1.3750
1.375 1.342 1.945 1.843 1.063 1.000 1.159 1.134
.109
.333
3.44
11⁄2
1.5000
1.500 1.464 2.121 2.010 1.159 1.091 1.284 1.259
.109
.333
3.75
Designation: Square head set screws are designated by the following data in the sequence shown:
Nominal size (number, fraction or decimal equivalent); threads per inch; screw length (fraction or
decimal equivalent); product name; point style; material; and protective finish, if required. Examples: 1⁄4 - 20 × 3⁄4 Square Head Set Screw, Flat Point, Steel, Cadmium Plated. .500 − 13 × 1.25 Square
Head Set Screw, Cone Point, Corrosion Resistant Steel.
Cone Point Angle, Y: For the following nominal lengths, or longer, shown according to nominal
size, the cone point angle is 90° ± 2°: For size No. 10, 1⁄4; 1⁄4, 5⁄16; 5⁄16, 3⁄8; 3⁄8, 7⁄16; 7⁄16, 1⁄2; 1⁄2, 9⁄16; 9⁄16, 5⁄8; 5⁄8, 3⁄4;
3⁄ , 7⁄ ; 7⁄ , 1; 1, 11⁄ ; 11⁄ , 11⁄ ; 11⁄ , 11⁄ ; 13⁄ , 15⁄ ; and for 11⁄ , 13⁄ . For shorter screws the cone point angle is
4 8 8
8
8
4
4
2
8
8
2
4
118° ± 2°.
Point Types: Unless otherwise specified, square head set screws are supplied with cup points. Cup
points as furnished by some manufacturers may be externally or internally knurled. Where so specified by the purchaser, screws have cone, dog, half-dog, flat or oval points as given on the following
page.
Point Angle, X: The point angle is 45°, + 5°, − 0° for screws of the nominal lengths, or longer, given
just above for cone point angle, and 30° min. for shorter lengths.
1630
SCREW SOCKET KEYS AND BITS
Table 14. Applicability of Hexagon and Spline Keys and Bits
Nominal
Key or Bit
Size
Cap Screws
1960 Series
Flat Countersunk
Head Cap Screws
Button Head
Cap Screws
Shoulder
Screws
Set
Screws
0
1&2
3&4
5&6
Nominal Screw Sizes
HEXAGON KEYS AND BITS
1⁄
16
0.062
…
…
0
1
5⁄
64
0.078
2&3
5&6
5&6
…
8
3⁄
32
0.094
4&5
8
8
…
10
7⁄
64
…
0.028
0.035
0.050
…
0
1&2
3&4
…
0
1&2
3&4
…
…
…
…
0.109
6
…
…
…
1⁄
8
0.125
…
10
10
1⁄
4
1⁄
4
9⁄
64
0.141
8
…
…
…
…
5⁄
16
5⁄
32
0.156
10
1⁄
4
1⁄
4
5⁄
16
3⁄
16
0.188
1⁄
4
5⁄
16
5⁄
16
3⁄
8
3⁄
8
7⁄
32
0.219
…
3⁄
8
3⁄
8
…
7⁄
16
1⁄
4
0.250
5⁄
16
7⁄
16
…
1⁄
2
1⁄
2
5⁄
16
0.312
3⁄
8
1⁄
2
1⁄
2
5⁄
8
5⁄
8
3⁄
8
0.375
7⁄ & 1⁄
16
2
5⁄
8
5⁄
8
3⁄
4
3⁄
4
7⁄
16
0.438
…
…
…
…
…
1⁄
2
0.500
5⁄
8
3⁄
4
…
1
7⁄
8
9⁄
16
0.562
…
7⁄
8
…
…
1 & 11⁄8
5⁄
8
0.625
3⁄
4
3⁄
4
0.750
7⁄ &
8
1
…
11⁄4
11⁄4 & 13⁄8
11⁄8
…
…
7⁄
8
0.875
11⁄2
11⁄8 & 11⁄4
11⁄4 & 13⁄8
…
11⁄2
…
13⁄4
13⁄4 & 2
…
1
1.000
13⁄8 & 11⁄2
11⁄2
…
11⁄4
1.250
13⁄4
…
…
2
11⁄2
1.500
2
…
…
…
…
1.750
21⁄4 &
…
…
…
…
2
2.000
23⁄4
…
…
…
…
21⁄4
2.250
3 & 31⁄4
…
…
…
…
…
…
…
…
…
…
…
…
0&1
2&3
4
5&6
8
10
…
1⁄
4
1
13⁄4
23⁄4
3
2.750
3.000
31⁄2 &
21⁄2
33⁄4
4
SPLINE KEYS AND BITS
…
…
0
1
2&3
4&5
6
…
8
10
…
0
1&2
3&4
5&6
8
…
10
…
1⁄
4
…
0
1&2
3&4
5&6
8
…
10
…
1⁄
4
…
…
…
…
…
…
…
…
…
…
0.216
1⁄
4
5⁄
16
5⁄
16
…
3⁄
8
0.251
…
3⁄
8
3⁄
8
…
7⁄
16
0.291
5⁄
16
7⁄
16
…
…
1⁄
2
0.372
3⁄
8
1⁄
2
1⁄
2
…
5⁄
8
0.454
7⁄ & 1⁄
16
2
5⁄ & 3⁄
8
4
5⁄
8
…
3⁄
4
0.595
5⁄
8
…
…
…
7⁄
8
0.620
3⁄
4
…
…
…
…
0.698
0.790
7⁄
8
…
…
…
…
…
…
…
…
0.033
0.048
0.060
0.072
0.096
0.111
0.133
0.145
0.168
0.183
1
Source: Appendix to American National Standard ANSI/ASME B18.3-1998.
…
5⁄
16
SCREW SOCKET KEYS AND BITS
1631
Table 15. ANSI Hexagon and Spline Socket Set Screws ANSI/ASME B18.3-1998
Flat Point
Oval Point
Cone Point
0
1
2
3
4
5
6
8
10
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
7⁄
8
1
11⁄8
11⁄4
13⁄8
11⁄2
13⁄4
2
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2500
0.3125
0.3750
0.4375
0.5000
0.6250
0.7500
0.8750
1.0000
1.1250
1.2500
1.3750
1.5000
1.7500
2.0000
Dia.
Max.
P
Lgth.
Max.
Q
Oval
Point
Radius
Basic
R
0.040
0.049
0.057
0.066
0.075
0.083
0.092
0.109
0.127
0.156
0.203
0.250
0.297
0.344
0.469
0.562
0.656
0.750
0.844
0.938
1.031
1.125
1.312
1.500
0.017
0.021
0.024
0.027
0.030
0.033
0.038
0.043
0.049
0.067
0.082
0.099
0.114
0.130
0.164
0.196
0.227
0.260
0.291
0.323
0.354
0.385
0.448
0.510
0.045
0.055
0.064
0.074
0.084
0.094
0.104
0.123
0.142
0.188
0.234
0.281
0.328
0.375
0.469
0.562
0.656
0.750
0.844
0.938
1.031
1.125
1.321
1.500
0.050
0.060
0.060
0.070
0.070
0.080
0.080
0.090
0.100
0.125
0.156
0.188
0.219
0.250
0.312
0.375
0.500
0.562
0.562
0.625
0.625
0.750
1.000
1.000
Half Dog
Cup Point
Socket Size
Nominal
Size
or Basic
Screw Diameter
For optional cup points and
their dimensions see Table 10.
Min. Key
Engagement
Lgth.
Depth
Limit for
Hex.
Spl.
Angle
T Ha
TSa
Yb
Hex.
Nom.
J
Spl.
Nom.
M
0.028
0.035
0.035
0.050
0.050
1⁄
16
1⁄
16
5⁄
64
3⁄
32
1⁄
8
5⁄
32
3⁄
16
7⁄
32
1⁄
4
5⁄
16
3⁄
8
1⁄
2
9⁄
16
9⁄
16
5⁄
8
5⁄
8
3⁄
4
1
1
0.033
0.033
0.048
0.048
0.060
0.072
0.072
0.096
0.111
0.145
0.183
0.216
0.251
0.291
0.372
0.454
0.595
…
…
…
…
…
…
…
Half Dog Point
Cup and Flat Point
Diameters
Max.
Min.
C
0.033
0.040
0.047
0.054
0.061
0.067
0.074
0.087
0.102
0.132
0.172
0.212
0.252
0.291
0.371
0.450
0.530
0.609
0.689
0.767
0.848
0.926
1.086
1.244
0.027
0.033
0.039
0.045
0.051
0.057
0.064
0.076
0.088
0.118
0.156
0.194
0.232
0.270
0.347
0.425
0.502
0.579
0.655
0.733
0.808
0.886
1.039
1.193
0.026
0.035
0.040
0.040
0.045
0.055
0.055
0.080
0.080
0.125
0.156
0.188
0.219
0.250
0.312
0.375
0.500
…
…
…
…
…
…
…
0.09
0.09
0.13
0.13
0.19
0.19
0.19
0.25
0.25
0.31
0.38
0.44
0.50
0.57
0.75
0.88
1.00
1.13
1.25
1.50
1.63
1.75
2.00
2.25
a Reference should be made to the Standard for shortest optimum nominal lengths to which the minimum key engagement depths TH and TS apply.
b Cone point angle Y is 90 degrees plus or minus 2 degrees for these nominal lengths or longer and
118 degrees plus or minus 2 degrees for shorter nominal lengths.
All dimensions are in inches. The thread conforms to the Unified Standard, Class 3A, UNC and
UNF series. The socket depth T is included in the Standard and some are shown here. The nominal
length L of all socket type set screws is the total or overall length. For nominal screw lengths of 1⁄16
through 3⁄16 inch (0 through 3 sizes incl.) the standard length increment is 0.06 inch; for lengths 1⁄8
through 1 inch the increment is 1⁄8 inch; for lengths 1 through 2 inches the increment is 1⁄4 inch; for
lengths 2 through 6 inches the increment is 1⁄2 inch; for lengths 6 inches and longer the increment is 1
inch. Socket dimensions are given in Table 11.
Length Tolerance: The allowable tolerance on length L for all set screws of the socket type is ± 0.01
inch for set screws up to 5⁄8 inch long; ± 0.02 inch for screws over 5⁄8 to 2 inches long; ± 0.03 inch for
screws over 2 to 6 inches long and ± 0.06 inch for screws over 6 inches long. Socket dimensions are
given in Table 11.
For manufacturing details, including materials, not shown, see American National Standard
ANSI/ASME B18.3-1998.
1632
HEXAGON SOCKET SCREWS
British Standard Hexagon Socket Screws — Metric Series.—The first five parts of
British Standard BS 4168: 1981 provide specifications for hexagon socket head cap
screws and hexagon socket set screws.
Hexagon Socket Head Cap Screws: The dimensional data in Table 1 are based upon BS
4168: Part 1: 1981. These screws are available in stainless steel and alloy steel, the latter
having class 12.9 properties as specified in BS 6104:Part 1. When ordering these screws,
the designation “Hexagon socket head cap screw BS 4168 M5 × 20-12.9” would mean, as
an example, a cap screw having a thread size of d = M5, nominal length l = 20 mm, and
property class 12.9. Alloy steel cap screws are furnished with a black oxide finish (thermal
or chemical); stainless steel cap screws with a plain finish. Combinations of thread size,
nominal length, and length of thread are shown in Table 2; the screw threads in these combinations are in the ISO metric coarse pitch series specified in BS 3643 with tolerances in
the 5g6g class. (See Metric Screw Threads in Index.)
Hexagon Socket Set Screws: Part 2 of B.S. 4168:1981 specifies requirements for hexagon socket set screws with fiat point having ISO metric threads, and diameters from 1.6
mm up to and including 24 mm. The dimensions of these set screws along with those of
cone-point, dog-point, and cup-point set screws in accord, respectively, with Parts 3, 4, and
5 of the Standard are given in Table 3 and the accompanying illustration. All of these set
screws are available in either steel processed to mechanical properties class 45H B.S.
6104:Part 3; or stainless steel processed to mechanical properties described in B.S. 6105.
Steel set screws are furnished with black oxide (thermal or chemical) finish; stainless steel
set screws are furnished plain. The tolerances applied to the threads of these set screws are
for ISO product grade A, based on ISO 4759⁄1-1978 “Tolerances for fasteners — Part 1:
Bolts, screws, and nuts with thread diameters greater than or equal to 1.6 mm and less than
or equal to 150 mm and product grades A, B, and C.”
Hexagon socket set screws are designated by the type, the thread size, nominal length,
and property class. As an example, for a flat-point set screw of thread size d = M6, nominal
length l = 12 mm, and property class 45H:
Hexagon socket set screw flat point BS 4168 M6 × 12-45H
British Standard Hexagon Socket Countersunk and Button Head Screws — Metric
Series: British Standard BS 4168:1967 provides a metric series of hexagon socket countersunk and button head screws. The dimensions of these screws are given in Table 4. The
revision of this Standard will constitute Parts 6 and 8 of BS 4168.
British Standards for Mechanical Properties of Fasteners: B.S. 6104: Part 1:1981 specifies mechanical properties for bolts, screws, and studs with nominal diameters up to and
including 39 mm of any triangular ISO thread and made of carbon or alloy steel. It does not
apply to set screws and similar threaded fasteners. Part 2 of this Standard specifies the
mechanical properties of set screws and similar fasteners, not under tensile stress, in the
range from M1.6 up to and including M39 and made of carbon or alloy steel.
B.S. 6105:1981 provides specifications for bolts, screws, studs, and nuts made from austenitic, ferritic, and martensitic grades of corrosion-resistant steels. This Standard applies
only to fastener components after completion of manufacture with nominal diameters
from M1.6 up to and including M39. These Standards are not described further here. Copies may be obtained from the British Standards Institution, 2 Park Street, London W1A
2BS and also from the American National Standards Institute, 25 West 43rd Street, New
York, N.Y. 10036.
Table 1. British Standard Hexagon Socket Head Cap Screws—Metric Series
BS 4168:Part 1:1981 (obsolescent)
Body
Diameter,
D
Max
1.6
2
2.5
3
4
5
6
8
10
12
14
16
20
24
30
36
Min
1.46
1.86
2.36
2.86
3.82
4.82
5.82
7.78
9.78
11.73
13.73
15.73
19.67
23.67
29.67
35.61
Maxc
3
3.8
4.5
5.5
7
8.5
10
13
16
18
21
24
30
36
45
54
Head
Diameter,
A
Maxd
3.14
3.98
4.68
5.68
7.22
8.72
10.22
13.27
16.27
18.27
21.33
24.33
30.33
36.39
45.39
54.46
Head
Height,
H
Min
2.86
3.62
4.32
5.32
6.78
8.28
9.78
12.73
15.73
17.73
20.67
23.67
29.67
35.61
44.61
53.54
Max
1.6
2
2.5
3
4
5
6
8
10
12
14
16
20
24
30
36
Min
1.46
1.86
2.36
2.86
3.82
4.82
5.70
7.64
9.64
11.57
13.57
15.57
19.48
23.48
29.48
35.38
Hexagon
Socket Size,
Jb
Nom
1.5
1.5
2
2.5
3
4
5
6
8
10
12
14
17.
19
22
27
Key
Engagement,
K
Min
0.7
1
1.1
1.3
2
2.5
3
4
5
6
7
8
10
12
15.5
19
Wall
Thickness,
W
Min
0.55
0.55
0.85
1.15
1.4
1.9
2.3
3.3
4
4.8
5.8
6.8
8.6
10.4
13.1
15.3
Fillet
Dia.,
Rad.,
da
F
Min
Max
0.1
2
0.1
2.6
0.1
3.1
0.1
3.6
0.2
4.7
0.2
5.7
0.25
6.8
0.4
9.2
0.4
11.2
0.6
14.2
0.6
16.2
0.6
18.2
0.8
22.4
0.8
26.4
1
33.4
1
39.4
CAP SCREWS
Nominal
Size,a
d
M1.6
M2
M2.5
M3
M4
M5
M6
M8
M10
M12
(M14)
M16
M20
M24
M30
M36
a The size shown in ( ) is non-preferred.
b See Table 2 for min/max.
c For plain heads.
1633
d For knurled heads.
All dimensions are given in millimeters.
1634
SCREW SOCKETS
Table 2. British Standard Hexagon Socket Screws — Metric Series
BS 4168:Part 1:1981 (obsolescent)
Dimensions of Hexagon Sockets
Socket Width Across Flats, J
Nominal
Socket Size
Socket Width Across Flats, J
Max.
Min.
Nominal
Socket Size
1.5
1.545
1.52
6
6.095
2.0
2.045
2.02
8
8.115
8.025
2.5
2.56
2.52
10
10.115
10.025
3
3.08
3.02
12
12.142
12.032
4
4.095
4.02
14
14.142
14.032
5
5.095
5.02
17
17.23
17.05
…
…
19
19.275
19.065
…
Max.
Min.
6.02
15
16
17
18
20
22
24
28
M36
…
…
M30
…
…
M24
…
…
M20
…
…
M16
…
…
(M14)
…
…
M12
…
…
Nominal
Length, L
M8
M6
M5
M4
M3
M2.5
M2
…
…
16
20
25
30
35
40
45
50
55
60
65
70
80
90
100
110
120
130
140
150
160
180
200
b
(ref)
Nominal Thread Size, D
M10
2.5
3
4
5
6
8
10
12
16
20
25
30
35
40
45
50
55
60
65
70
80
…
…
b
(ref)
Nominal Thread Size, D
M1.6
Nominal
Length, L
Association of Nominal and Thread Lengths for Each Thread Size
32
36
40
44
52
60
72
84
The popular lengths are those between the stepped solid lines. Lengths above the shaded areas are
threaded to the head within 3 pitch lengths (3P). Lengths within and below the shaded areas have values of Lg and Ls (see Table 1) given by the formulas: Lgmax = L nom − b ref, and Lsmin = Lgmax − 5P.
Table 3. British Standard Hexagon Socket Set Screws — Metric Series
BS 4168:Parts 2, 3, 4, and 5:1994
Socket
Size,
s
Depth of
Key
Engagement,
ta
Length of Dog on Dog Point Screwsb
Range of Popular Lengths
Flat
Point
Cone
Point
Dog
Point
Cup
Point
Short Dog,
z
End Diameters
Cone
Point
dt
Dog
Point,
dp
Cup
Point,
dz
b
max
max
max
max
2.5
0.8
0
0.8
0.8
3.0
1.0
0
1.0
1.0
1.5
4
1.5
0
1.5
1.2
1.75
5
2.0
0
2.0
1.4
Pitch,
P
nom
min
min
l
l
l
l
min
M1.6
0.35
0.7
0.7
1.5
2–8
2–8
2–8
2–8
0.4
0.65
0.8
1.05
M2
0.4
0.9
0.8
1.7
2–10
2–10
2.5–10
2–10
0.5
0.75
1.0
1.25
M2.5
0.45
1.3
1.2
2.0
2–12
2.5–12
3–12
2–12
0.63
0.88
1.25
M3
0.5
1.5
1.2
2.0
2–16
2.5–16
4–16
2.5–16
0.75
1.0
1.5
M4
0.7
2.0
1.5
2.5
2.5–20
3–20
5–20
3–20
1.0
1.25
2.0
2.25
6
2.5
0
2.5
2.0
M5
0.8
2.5
2.0
3.0
3–25
4–25
6–25
4–25
1.25
1.5
2.5
2.75
6
3.5
0
3.5
2.5
M6
1.0
3.0
2.0
3.5
4–30
5–30
8–30
5–30
1.5
1.75
3.0
3.25
8
4.0
1.5
4.0
3.0
M8
1.25
4.0
3.0
5.0
5–40
6–40
8–40
6–40
2.0
2.25
4.0
4.3
10
5.5
2.0
5.5
5.0
M10
1.5
5.0
4.0
6.0
6–50
8–50
10–50
8–50
2.5
2.75
5.0
5.3
12
7.0
2.5
7.0
6.0
M12
1.75
6.0
4.8
8.0
8–60
10–60
12–60
10–60
3.0
3.25
6.0
6.3
16
8.5
3.0
8.5
8.0
M16
2.0
8.0
6.4
10.0
10–60
12–60
16–60
12–60
4.0
4.3
8.0
8.36
20
12.0
4.0
12.0
10.0
M20
2.5
10.0
8.0
12.0
12–60
16–60
20–60
16–60
5.0
5.3
10.0
10.36
25
15.0
5.0
15.0
14.0
M24
3.0
12.0
10.0
15.0
16–60
20–60
25–60
20–60
6.0
6.3
12.0
12.43
30
18.0
6.0
18.0
16.0
max
min
max
SCREW SOCKETS
Flat
Point,
dz
Long Dog,
z
Nom.
Size,
d
a The smaller of the two t min. values applies to certain short-length set screws. These short-length screws are those whose length is approximately equal to the diameter
All dimensions are in millimeters. For dimensional notation, see diagram, page 1637.
1635
of the screw. The larger t min. values apply to longer-length screws.
b A dog point set screw having a nominal length equal to or less than the length shown in the (*) column of the table is supplied with length z shown in the short dog
column. For set screws of lengths greater than shown in the (*) column, z for long dogs applies.
1636
SCREW SOCKETS
Table 4. British Standard Hexagon Socket Countersunk and
Button Head Screws — Metric Series BS 4168:1967
COUNTERSUNK HEADSCREWS
Body
Diameter,
D
Head
Diameter,
A
Head
Height,
H
Hexagon
Socket
Size,
J
Key
Engagement,
K
Fillet
Radius,
F
Max.
Min.
Theor.
Sharp
Max.
Nom.
Min.
Max.
M3
3.00
2.86
6.72
5.82
1.86
0.20
2.00
1.05
0.40
M4
4.00
3.82
8.96
7.78
2.48
0.20
2.50
1.49
0.40
M5
5.00
4.82
11.20
9.78
3.10
0.20
3.00
1.86
0.40
Nom.
Sizea
M6
Absolute
Min.
Ref.
Flushness
Tolerance
6.00
5.82
13.44
11.73
3.72
0.20
4.00
2.16
0.60
M8
8.00
7.78
17.92
15.73
4.96
0.24
5.00
2.85
0.70
M10
10.00
9.78
22.40
19.67
6.20
0.30
6.00
3.60
0.80
M12
12.00
11.73
26.88
23.67
7.44
0.36
8.00
4.35
1.10
(M14)
14.00
13.73
30.24
26.67
8.12
0.40
10.00
4.65
1.10
M16
16.00
15.73
33.60
29.67
8.80
0.45
10.00
4.89
1.10
(M18)
18.00
17.73
36.96
32.61
9.48
0.50
12.00
5.25
1.10
M20
20.00
19.67
40.32
35.61
10.16
0.54
12.00
5.45
1.10
a Sizes shown in parentheses are non-preferred.
BUTTON HEADSCREWS
Nom.
Size,
D
Head
Diameter,
Head
Height,
Head
Side
Height,
Hexagon
Socket
Size,
Key
Engagement,
A
H
S
J
K
F
da
Fillet Radius
Max.
Min.
Max.
Min.
Ref.
Nom.
Min.
Min.
Max.
M3
5.50
5.32
1.60
1.40
0.38
2.00
1.04
0.10
3.60
M4
7.50
7.28
2.10
1.85
0.38
2.50
1.30
0.20
4.70
M5
9.50
9.28
2.70
2.45
0.50
3.00
1.56
0.20
5.70
M6
10.50
10.23
3.20
2.95
0.80
4.00
2.08
0.25
6.80
M8
14.00
13.73
4.30
3.95
0.80
5.00
2.60
0.40
9.20
M10
18.00
17.73
5.30
4.95
0.80
6.00
3.12
0.40
11.20
M12
21.00
20.67
6.40
5.90
0.80
8.00
4.16
0.60
14.20
All dimensions are given in millimeters.
SET SCREWS
1637
British Standard Hexagon Socket Set Screws — Metric Series
BS 4168:Parts 2, 3, 4, and 5:1994
FLAT POINT
CUP POINT
DOG POINT
CONE POINT
ALTERNATE CONE POINT
(M6 AND LARGER)
*The 120° angle is mandatory for short-length screws shown in the Standard. Short-length screws
are those whose length is, approximately, equal to the diameter of the screw.
**The 45° angle applies only to that portion of the point below the root diameter, df, of the thread.
***The cone angle applies only to the portion of the point below the root diameter, df, of the thread
and shall be 120° for certain short lengths listed in the Standard. All other lengths have a 90° cone
angle.
†The popular length ranges of these set screws are listed in Table 3. These lengths have been
selected from the following nominal lengths: 2, 2.5, 3, 4, 6, 8, 10, 12, 16, 20, 25,30, 35, 40, 45, 50, 55,
and 60 millimeters.
Holding Power of Set-screws.—While the amount of power a set-screw of given size
will transmit without slipping (when used for holding a pulley, gear, or other part from
turning relative to a shaft) varies somewhat according to the physical properties of both
set-screw and shaft and other variable factors, experiments have shown that the safe holding force in pounds for different diameters of set-screws should be approximately as follows: For 1⁄4-inch diameter set-screws the safe holding force is 100 pounds, for 3⁄8-inch
1638
COUNTERSUNK AND BUTTON HEAD SCREWS
diameter set-screws the safe holding force is 250 pounds, for 1⁄2-inch diameter set-screws
the safe holding force is 500 pounds, for 3⁄4-inch diameter set-screws the safe holding force
is 1300 pounds, and for 1-inch diameter set-screws the safe holding force is 2500 pounds.
The power or torque that can be safely transmitted by a set-screw may be determined
from the formulas, P = (DNd2.3) ÷ 50; or T = 1250Dd2.3 in which P is the horsepower transmitted; T is the torque in inch-pounds transmitted; D is the shaft diameter in inches; N is the
speed of the shaft in revolutions per minute; and d is the diameter of the set-screw in inches.
Example:How many 1⁄2-inch diameter set-screws would be required to transmit 3 horsepower at a shaft speed of 1000 rpm if the shaft diameter is 1 inch?
Using the first formula given above, the power transmitted by a single 1⁄2-inch diameter
set-screw is determined: P = [1 × 1000 × (1⁄2)2.3] ÷ 50 = 4.1 hp. Therefore a single 1⁄2-inch
diameter set-screw is sufficient.
Example:In the previous example, how many 3⁄8-inch diameter set-screws would be
required? P = [1 × 1000 × (3⁄8)2.3] ÷ 50 = 2.1 hp. Therefore two 3⁄8-inch diameter set-screws
are required.
Table 5. British Standard Whitworth (BSW) and British Standard Fine (BSF) Bright
Square Head Set-Screws (With Flat Chamfered Ends)
No. 1 Standard
Nominal
Size and
Max.
Dia.,
Inches
1
Number
of Threads
per Inch
No. 2 Standard
No. 3 Standard
Depth
of
Head
B
Width
Across
Flats
C
Depth
of
Head
D
Width
Across
Flats
E
Depth
of
Head
F
BSF
Width
Across
Flats
A
1⁄
4
20
26
0.250
0.250
0.313
0.250
0.375
0.250
5⁄
16
18
22
0.313
0.313
0.375
0.313
0.438
0.313
3⁄
8
16
20
0.375
0.375
0.438
0.375
0.500
0.375
7⁄
16
14
18
0.438
0.438
0.500
0.438
0.625
0.438
1⁄
2
12
16
0.500
0.500
0.563
0.500
0.750
0.500
5⁄
8
11
14
0.625
0.625
0.750
0.625
0.875
0.625
3⁄
4
10
12
0.750
0.750
0.875
0.750
1.000
0.750
7⁄
8
9
11
0.875
0.875
1.000
0.875
1.125
0.875
8
10
1.000
1.000
1.125
1.000
1.250
1.000
BSW
* Depth of Head B, D and F same as for Width Across Flats, No. 1 Standard.
Dimensions A, B, C, D, E, and F are in inches.
SELF-THREADING SCREWS
1639
ANSI Standard Sheet Metal, Self-Tapping, and Metallic Drive Screws.—T a b l e 1
shows the various types of “self-tapping” screw threads covered by the ANSI B18.6.41981 (R1991) standard. (Metric thread forming and thread cutting tapping screws are discussed beginning on page 1654). ANSI designations are also shown. Types A, AB, B, BP
and C when turned into a hole of proper size form a thread by a displacing action. Types D,
F, G, T, BF and BT when turned into a hole of proper size form a thread by a cutting action.
Type U when driven into a hole of proper size forms a series of multiple threads by a displacing action. These screws have the following descriptions and applications:
Type A: Spaced-thread screw with gimlet point primarily for use in light sheet metal,
resin-impregnated plywood, and asbestos compositions. This type is no longer recommended. Use Type AB in new designs and whenever possible substitute for Type A in
existing designs.
Type AB: Spaced-thread screw with same pitches as Type B but with gimlet point, primarily for similar uses as for Type A.
Type B: Spaced-thread screw with a blunt point with pitches generally somewhat finer
than Type A. Used for thin metal, non-ferrous castings, plastics, resin-impregnated plywood, and asbestos compositions.
Type BP: Spaced-thread screw, the same as Type B but having a conical point extending
beyond incomplete entering threads. Used for piercing fabrics or in assemblies where
holes are misaligned.
Type C: Screws having machine screw diameter-pitch combinations with threads
approximately Unified Form and with blunt tapered points. Used where a machine screw
thread is preferable to the spaced-thread types of thread forming screws. Also useful when
chips from machine screw thread-cutting screws are objectionable. In view of the declining use of Type C screws, which in general require high driving torques, in favor of more
efficient designs of thread tapping screws, they are not recommended for new designs.
Types D, F, G, and T: Thread-cutting screws with threads approximating machine screw
threads, with blunt point, and with tapered entering threads having one or more cutting
edges and chip cavities. The tapered threads of the Type F may be complete or incomplete
at the producer's option; all other types have incomplete tapered threads. These screws can
be used in materials such as aluminum, zinc, and lead die-castings; steel sheets and shapes;
cast iron; brass; and plastics.
Types BF and BT: Thread-cutting screws with spaced threads as in Type B, with blunt
points, and one or more cutting grooves. Used in plastics, asbestos, and other similar compositions.
Type U: Multiple-threaded drive screw with large helix angle, having a pilot point, for
use in metal and plastics. This screw is forced into the work by pressure and is intended for
making permanent fastenings.
ANSI Standard Head Types for Tapping and Metallic Drive Screws: Many of the head
types used with “self-tapping” screw threads are similar to the head types of American
National Standard machine screws shown in the section with that heading.
Round Head: The round head has a semi-elliptical top surface and a flat bearing surface.
Because of the superior slot driving characteristics of pan head screws over round head
screws, and the overlap in dimensions of cross recessed pan heads and round heads, it is
recommended that pan head screws be used in new designs and wherever possible substituted in existing designs.
Undercut Flat and Oval Countersunk Heads: For short lengths, 82-degree and oval
countersunk head tapping screws have heads undercut to 70 per cent of normal side height
to afford greater length of thread on the screws.
1640
Flat Countersunk Head: The flat countersunk head has a flat top surface and a conical
bearing surface with a head angle for one design of approximately 82 degrees and for
another design of approximately 100 degrees. Because of its limited usage and in the interest of curtailing product varieties, the 100-degree flat countersunk head is considered nonpreferred.
Oval Countersunk Head: The oval countersunk head has a rounded top surface and a
conical bearing surface with a head angle of approximately 82 degrees.
Flat and Oval Countersunk Trim Heads: Flat and oval countersunk trim heads are similar to the 82-degree flat and oval countersunk heads except that the size of head for a given
size screw is one (large trim head) or two (small trim head) sizes smaller than the regular
flat and oval countersunk head size. Oval countersunk trim heads have a definite radius
where the curved top surface meets the conical bearing surface. Trim heads are furnished
only in cross recessed types.
Pan Head: The slotted pan head has a flat top surface rounded into cylindrical sides and
a flat bearing surface. The recessed pan head has a rounded top and a flat bearing surface.
This head type is now preferred to the round head.
Fillister Head: The fillister head has a rounded top surface, cylindrical sides, and a flat
bearing surface.
Hex Head: The hex head has a flat or indented top surface, six flat sides, and a flat bearing surface. Because the slotted hex head requires a secondary operation in manufacture
which often results in burrs at the extremity of the slot that interfere with socket wrench
engagement and the wrenching capability of the hex far exceeds that of the slot, it is not
recommended for new designs.
Hex Washer Head: The hex washer head has an indented top surface and six flat sides
formed integrally with a flat washer that projects beyond the sides and provides a flat bearing surface. Because the slotted hex washer head requires a secondary operation in manufacture which often results in burrs at the extremity of the slot that often interferes with
socket wrench engagement and because the wrenching capability of the hex far exceeds
that of the slot in the indented head, it is not recommended for new designs.
Truss Head: The truss head has a low rounded top surface with a flat bearing surface, the
diameter of which for a given screw size is larger than the diameter of the corresponding
round head. In the interest of product simplification and recognizing that the truss head is
an inherently weak design, it is not recommended for new designs.
Method of Designation.—Tapping screws are designated by the following data in the
sequence shown: Nominal size (number, fraction or decimal equivalent); threads per inch;
nominal length (fraction or decimal equivalent); point type; product name, including head
type and driving provision; material; and protective finish, if required.
Examples:
1⁄ –14 × 11⁄ Type AB Slotted Pan Head Tapping Screw, Steel, Nickel Plated
4
2
6–32 × 3⁄4 Type T, Type 1A Cross Recessed Pan Head Tapping Screw, Corrosion Resistant Steel
0.375–16 × 1.50 Type D, Washer Head Tapping Screw, Steel
Metallic Drive Screws: Type U metallic drive screws are designated by the following
data in the sequence shown: Nominal size (number, fraction, or decimal equivalent); nominal length (fraction or decimal equivalent); product name, including head type; material;
and protective finish, if required. Examples:
10 × 5⁄16 Round Head Metallic Drive Screw, Steel
0.312 × 0.50 Round Head Metallic Drive Screw, Steel, Zinc Plated
1641
Table 1. ANSI Standard Threads and Points for Thread Forming Self-Tapping
Screws ANSI B18.6.4-1981 (R1991)
See Tables 3, 5, and 6 for thread data.
1642
Table 2. ANSI Standard Threads and Points for Thread Cutting
Self-Tapping Screws ANSI B18.6.4-1981 (R1991)
See Tables 5 and 7 for thread data.
Cross Recesses.—Type I cross recess has a large center opening, tapered wings, and blunt
bottom, with all edges relieved or rounded. Type IA cross recess has a large center opening, wide straight wings, and blunt bottom, with all edges relieved or rounded. Type II consists of two intersecting slots with parallel sides converging to a slightly truncated apex at
the bottom of the recess. Type III has a square center opening, slightly tapered side walls,
and a conical bottom, with top edges relieved or rounded.
Table 3. ANSI Standard Cross Recesses for Self-Tapping Screws
ANSI B18.6.4-1981 (R1991) and Metric Thread Forming and Thread
Cutting Tapping Screws ANSI/ASME B18.6.5M-1986
TYPE I
TYPE IA
TYPE II
TYPE III
1643
Table 4. ANSI Standard Thread and Point Dimensions for Types AB, A and U
Thread Forming Tapping Screws ANSI B18.6.4-1981 (R1991)
Nominal
Size or Basic
Screw
Diameter
0
1
2
3
4
5
6
7
8
10
12
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1510
0.1640
0.1900
0.2160
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
0.2500
0.3125
0.3750
0.4375
0.5000
Type AB (Formerly BA)
D
d
Major
Minor
Diameter
Diameter
Max.
Min.
Max.
Min.
Threads
per inch
48
42
32
28
24
20
20
19
18
16
14
14
12
12
10
10
0.060
0.075
0.088
0.101
0.114
0.130
0.139
0.154
0.166
0.189
0.215
0.246
0.315
0.380
0.440
0.504
0.054
0.069
0.082
0.095
0.108
0.123
0.132
0.147
0.159
0.182
0.208
0.237
0.306
0.371
0.429
0.493
0.036
0.049
0.064
0.075
0.086
0.094
0.104
0.115
0.122
0.141
0.164
0.192
0.244
0.309
0.359
0.423
L
Minimum Practical
Screw Lengths
90° Heads Csk. Heads
1⁄
8
5⁄
32
3⁄
16
3⁄
16
7⁄
32
1⁄
4
9⁄
32
5⁄
16
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
7⁄
8
0.033
0.046
0.060
0.071
0.082
0.090
0.099
0.109
0.116
0.135
0.157
0.185
0.236
0.299
0.349
0.413
5⁄
32
3⁄
16
7⁄
32
1⁄
4
9⁄
32
5⁄
16
11⁄
32
3⁄
8
3⁄
8
7⁄
16
21⁄
32
19⁄
32
3⁄
4
29⁄
32
11⁄32
15⁄32
1
Type A
Nominal
Sizea Basic
Screw Diameter
0
1
2
3
4
5
6
7
8
10
12
14
16
18
20
24
Threads
per inch
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1510
0.1640
0.1900
0.2160
0.2420
0.2680
0.2940
0.3200
0.3720
40
32
32
28
24
20
18
16
15
12
11
10
10
9
9
9
D
d
Major Diameter
Max.
Min.
Minor Diameter
Max.
Min.
0.060
0.075
0.088
0.101
0.114
0.130
0.141
0.158
0.168
0.194
0.221
0.254
0.280
0.306
0.333
0.390
0.042
0.051
0.061
0.076
0.083
0.095
0.102
0.114
0.123
0.133
0.162
0.185
0.197
0.217
0.234
0.291
0.057
0.072
0.084
0.097
0.110
0.126
0.136
0.152
0.162
0.188
0.215
0.248
0.274
0.300
0.327
0.383
L
These Lengths or Shorter
—Use Type AB
90° Heads Csk. Heads
1⁄
8
1⁄
8
5⁄
32
3⁄
16
3⁄
16
3⁄
16
1⁄
4
5⁄
16
3⁄
8
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
11⁄
16
3⁄
4
0.039
0.048
0.056
0.071
0.078
0.090
0.096
0.108
0.116
0.126
0.155
0.178
0.189
0.209
0.226
0.282
3⁄
16
3⁄
16
3⁄
16
7⁄
32
1⁄
4
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
9⁄
16
5⁄
8
3⁄
4
13⁄
16
13⁄
16
1
a Where specifying nominal size in decimals, zeros preceding decimal and in fourth place are omit-
ted.
Type U Metallic Drive Screws
Out. Dia.
Pilot Dia.
Out. Dia.
Pilot Dia.
Nom.
Size
No. of
Starts
Max.
Min.
Max.
Min.
Nom.
Size
No. of
Starts
Max.
Min.
Max.
Min.
00
0
2
4
6
6
6
8
7
7
0.060
0.075
0.100
0.116
0.140
0.057
0.072
0.097
0.112
0.136
0.049
0.063
0.083
0.096
0.116
0.046
0.060
0.080
0.092
0.112
8
10
12
14
5⁄
16
8
8
8
9
11
0.167
0.182
0.212
0.242
0.315
0.162
0.177
0.206
0.236
0.309
0.136
0.150
0.177
0.202
0.272
0.132
0.146
0.173
0.198
0.267
7
8
0.154
0.150
0.126
0.122
3⁄
8
12
0.378
0.371
0.334
0.329
All dimensions are in inches. See Table 1 for thread diagrams.
Sizes shown in bold face type are preferred. Type A screws are no longer recommended.
1644
Table 5. ANSI Standard Thread and Point Dimensions for B and BP Thread Forming and BF and BT Thread Cutting Tapping Screws ANSI B18.6.4-1981 (R1991)
THREAD FORMING TYPES B AND BP
d
P
S
D
Nominal
Sizea
or Basic
Screw
Diameter
0 0.0600
1 0.0730
2 0.0860
3 0.0990
4 0.1120
5 0.1250
6 0.1380
7 0.1510
8 0.1640
10 0.1900
12 0.2160
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
0.2500
0.3125
0.3750
0.4375
0.5000
Major
Diameter
Thds
per
Inchb
48
42
32
28
24
20
20
19
18
16
14
14
12
12
10
10
Max
0.060
0.075
0.088
0.101
0.114
0.130
0.139
0.154
0.166
0.189
0.215
0.246
0.315
0.380
0.440
0.504
Min
0.054
0.069
0.082
0.095
0.108
0.123
0.132
0.147
0.159
0.182
0.208
0.237
0.306
0.371
0.429
0.493
Max
0.036
0.049
0.064
0.075
0.086
0.094
0.104
0.115
0.122
0.141
0.164
0.192
0.244
0.309
0.359
0.423
Min
0.033
0.046
0.060
0.071
0.082
0.090
0.099
0.109
0.116
0.135
0.157
0.185
0.236
0.299
0.349
0.413
Point
Taper
Lengthd
Point
Diameterc
Minor
Diameter
Max
0.031
0.044
0.058
0.068
0.079
0.087
0.095
0.105
0.112
0.130
0.152
0.179
0.230
0.293
0.343
0.407
Min
0.027
0.040
0.054
0.063
0.074
0.082
0.089
0.099
0.106
0.123
0.145
0.171
0.222
0.285
0.335
0.399
Max
0.042
0.048
0.062
0.071
0.083
0.100
0.100
0.105
0.111
0.125
0.143
0.143
0.167
0.167
0.200
0.200
Min
0.031
0.036
0.047
0.054
0.063
0.075
0.075
0.079
0.083
0.094
0.107
0.107
0.125
0.125
0.150
0.150
L
Minimum Practical
Nominal Screw Lengths
Type B
Type BP
90°
Csk
90°
Csk
Heads Heads Heads Heads
1⁄
8
1⁄
8
5⁄
32
3⁄
16
3⁄
16
7⁄
32
1⁄
4
1⁄
4
9⁄
32
5⁄
16
11⁄
32
3⁄
8
15⁄
32
17⁄
32
5⁄
8
11⁄
16
1⁄
8
5⁄
32
3⁄
16
7⁄
32
1⁄
4
9⁄
32
9⁄
32
5⁄
16
11⁄
32
3⁄
8
7⁄
16
1⁄
2
19⁄
32
11⁄
16
25⁄
32
27⁄
32
5⁄
32
3⁄
16
1⁄
4
9⁄
32
5⁄
16
11⁄
32
3⁄
8
13⁄
32
7⁄
16
1⁄
2
9⁄
16
21⁄
32
27⁄
32
15⁄
16
1
1 ⁄8
11⁄4
3⁄
16
7⁄
32
9⁄
32
5⁄
16
11⁄
32
13⁄
32
7⁄
16
15⁄
32
1⁄
2
19⁄
32
21⁄
32
3⁄
4
31⁄
32
11⁄8
1
1 ⁄4
113⁄32
a Where specifying nominal size in decimals, zeros preceding decimal and in the fourth decimal
place shall be omitted.
b The width of flat at crest of thread shall not exceed 0.004 inch for sizes up to No. 8, inclusive, and
0.006 inch for larger sizes.
c Point diameters specified apply to screw threads before roll threading.
d Points of screws are tapered and fluted or slotted. The flute on Type BT screws has an included
angle of 90 to 95 degrees and the thread cutting edge is located above the axis of the screw. Flutes and
slots extend through first full form thread beyond taper except for Type BF screw on which tapered
threads may be complete at manufacturer's option and flutes may be one pitch short of first full form
thread.
THREAD CUTTING TYPES BF AND BTd
d
P
D
Nominal
Sizea
or Basic
Screw
Diameter
0 0.0600
1 0.0730
2 0.0860
3 0.0990
4 0.1120
5 0.1250
6 0.1380
7 0.1510
8 0.1640
10 0.1900
12 0.2160
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
0.2500
0.3125
0.3750
0.4375
0.5000
Thds
per
Inchb
48
42
32
28
24
20
20
19
18
16
14
14
12
12
10
10
Major
Diameter
Max
0.060
0.075
0.088
0.101
0.114
0.130
0.139
0.154
0.166
0.189
0.215
0.246
0.315
0.380
0.440
0.504
Min
0.054
0.069
0.082
0.095
0.108
0.123
0.132
0.147
0.159
0.182
0.208
0.237
0.306
0.371
0.429
0.493
Minor
Diameter
Max
0.036
0.049
0.064
0.075
0.086
0.094
0.104
0.115
0.122
0.141
0.164
0.192
0.244
0.309
0.359
0.423
Min
0.033
0.046
0.060
0.071
0.082
0.090
0.099
0.109
0.116
0.135
0.157
0.185
0.236
0.299
0.349
0.413
S
Point
Taper
Lengthd
Point
Diameterc
Max
0.031
0.044
0.058
0.068
0.079
0.087
0.095
0.105
0.112
0.130
0.152
0.179
0.230
0.293
0.343
0.407
Min
0.027
0.040
0.054
0.063
0.074
0.082
0.089
0.099
0.106
0.123
0.145
0.171
0.222
0.285
0.335
0.399
Max
0.042
0.048
0.062
0.071
0.083
0.100
0.100
0.105
0.111
0.125
0.143
0.143
0.167
0.167
0.200
0.200
Min
0.031
0.036
0.047
0.054
0.063
0.075
0.075
0.079
0.083
0.094
0.107
0.107
0.125
0.125
0.150
0.150
All dimensions are in inches. See Tables 1 and 2 for thread diagrams.
L
Minimum
Practical
Nominal
Screw Lengths
90°
Csk
Heads
Heads
1⁄
8
1⁄
8
5⁄
32
3⁄
16
3⁄
16
7⁄
32
1⁄
4
1⁄
4
9⁄
32
5⁄
16
11⁄
32
3⁄
8
15⁄
32
17⁄
32
5⁄
8
11⁄
16
1⁄
8
5⁄
32
3⁄
16
7⁄
32
1⁄
4
9⁄
32
9⁄
32
5⁄
16
11⁄
32
3⁄
8
7⁄
16
1⁄
2
19⁄
32
11⁄
16
25⁄
32
27⁄
32
Table 6. Thread and Point Dimensions for Type C Thread Forming Tapping Screws (ANSI B18.6.4–1981, R1991 Appendix)
Threads
per inch
56
64
48
56
40
48
40
44
32
40
32
36
24
32
24
28
20
28
18
24
16
24
14
20
13
20
D
P
Major Diameter
Max
Min
0.0860
0.0813
0.0860
0.0816
0.0990
0.0938
0.0990
0.0942
0.1120
0.1061
0.1120
0.1068
0.1250
0.1191
0.1250
0.1195
0.1380
0.1312
0.1380
0.1321
0.1640
0.1571
0.1640
0.1577
0.1900
0.1818
0.1900
0.1831
0.2160
0.2078
0.2160
0.2085
0.2500
0.2408
0.2500
0.2425
0.3125
0.3026
0.3125
0.3042
0.3750
0.3643
0.3750
0.3667
0.4375
0.4258
0.4375
0.4281
0.5000
0.4876
0.5000
0.4906
Point Diameterb
Max
Min
0.068
0.061
0.070
0.064
0.078
0.070
0.081
0.074
0.087
0.078
0.091
0.083
0.100
0.091
0.102
0.094
0.107
0.096
0.113
0.104
0.132
0.122
0.136
0.126
0.148
0.135
0.158
0.148
0.174
0.161
0.180
0.168
0.200
0.184
0.214
0.202
0.257
0.239
0.271
0.257
0.312
0.293
0.333
0.319
0.366
0.344
0.387
0.371
0.423
0.399
0.450
0.433
a Where specifying nominal size in decimals, zeros
S
Point Taper Lengthc
For Short Screws
For Long Screws
Max
Min
Max
Min
0.062
0.045
0.080
0.062
0.055
0.039
0.070
0.055
0.073
0.052
0.094
0.073
0.062
0.045
0.080
0.062
0.088
0.062
0.112
0.088
0.073
0.052
0.094
0.073
0.088
0.062
0.112
0.088
0.080
0.057
0.102
0.080
0.109
0.078
0.141
0.109
0.088
0.062
0.112
0.088
0.109
0.078
0.141
0.109
0.097
0.069
0.125
0.097
0.146
0.104
0.188
0.146
0.109
0.078
0.141
0.109
0.146
0.104
0.188
0.146
0.125
0.089
0.161
0.125
0.175
0.125
0.225
0.175
0.125
0.089
0.161
0.125
0.194
0.139
0.250
0.194
0.146
0.104
0.188
0.146
0.219
0.156
0.281
0.219
0.146
0.104
0.188
0.146
0.250
0.179
0.321
0.250
0.175
0.125
0.225
0.175
0.269
0.192
0.346
0.269
0.175
0.125
0.225
0.175
L
Determinant Lengths
for Point Taperc
90° Heads
Csk Heads
5⁄
32
1⁄
8
3⁄
16
5⁄
32
7⁄
32
3⁄
16
7⁄
32
3⁄
16
1⁄
4
7⁄
32
1⁄
4
7⁄
32
11⁄
32
1⁄
4
11⁄
32
5⁄
16
13⁄
32
5⁄
16
15⁄
32
11⁄
32
1⁄
2
11⁄
32
19⁄
32
13⁄
32
5⁄
8
13⁄
32
3⁄
16
3⁄
16
7⁄
32
3⁄
16
1⁄
4
7⁄
32
9⁄
32
1⁄
4
5⁄
16
9⁄
32
11⁄
32
5⁄
16
7⁄
16
11⁄
32
7⁄
16
13⁄
32
17⁄
32
13⁄
32
19⁄
32
15⁄
32
11⁄
16
1⁄
2
3⁄
4
9⁄
16
25⁄
32
9⁄
16
Minimum Practical
90° Heads
Csk Heads
5⁄
32
1⁄
8
5⁄
32
5⁄
32
3⁄
16
5⁄
32
3⁄
16
3⁄
16
1⁄
4
3⁄
16
1⁄
4
7⁄
32
5⁄
16
1⁄
4
5⁄
16
9⁄
32
3⁄
8
9⁄
32
7⁄
16
5⁄
16
15⁄
32
5⁄
16
9⁄
16
3⁄
8
19⁄
32
3⁄
8
3⁄
16
5⁄
32
7⁄
32
3⁄
16
1⁄
4
7⁄
32
1⁄
4
1⁄
4
5⁄
16
1⁄
4
5⁄
16
9⁄
32
13⁄
32
5⁄
16
13⁄
32
3⁄
8
1⁄
2
3⁄
8
9⁄
16
15⁄
32
5⁄
8
1⁄
2
23⁄
32
17⁄
32
3⁄
4
17⁄
32
Nominal
Sizeaor Basic
Screw Diameter
2 0.0860
2 0.0860
3 0.0990
3 0.0990
4 0.1120
4 0.1120
5 0.1250
5 0.1250
6 0.1380
6 0.1380
8 0.1640
8 0.1640
10 0.1900
10 0.1900
12 0.2160
12 0.2160
1⁄
4 0.2500
1⁄
4 0.2500
5⁄
16 0.3125
5⁄
16 0.3125
3⁄
8 0.3750
3⁄
8 0.3750
7⁄
16 0.4375
7⁄
16 0.4375
1⁄
2 0.5000
1⁄
2 0.5000
preceding decimal and in the fourth decimal place shall be omitted.
b The tabulated values apply to screw blanks before roll threading.
c Screws of these nominal lengths and shorter shall have point taper length specified above for short screws. Longer lengths shall have point taper length specified for
long screws.
1645
All dimensions are in inches. See Table 1 for thread diagrams. Type C is not recommended for new designs.
Tapered threads shall have unfinished crests.
1646
Table 7. ANSI Standard Thread and Point Dimensions for Types D, F, G, and T
Thread Cutting Tapping Screws ANSI B18.6.4-1981 (R1991)
Threads
per inch
56
64
48
56
40
48
40
44
32
40
32
36
24
32
24
28
20
28
18
24
16
24
14
20
13
20
D
Major
Diameter
Max
0.0860
0.0860
0.0990
0.0990
0.1120
0.1120
0.1250
0.1250
0.1380
0.1380
0.1640
0.1640
0.1900
0.1900
0.2160
0.2160
0.2500
0.2500
0.3125
0.3125
0.3750
0.3750
0.4375
0.4375
0.5000
0.5000
Min
0.0813
0.0816
0.0938
0.0942
0.1061
0.1068
0.1191
0.1195
0.1312
0.1321
0.1571
0.1577
0.1818
0.1831
0.2078
0.2085
0.2408
0.2425
0.3026
0.3042
0.3643
0.3667
0.4258
0.4281
0.4876
0.4906
P
Point
Diameterb
Max
0.068
0.070
0.078
0.081
0.087
0.091
0.100
0.102
0.107
0.113
0.132
0.136
0.148
0.158
0.174
0.180
0.200
0.214
0.257
0.271
0.312
0.333
0.366
0.387
0.423
0.450
Min
0.061
0.064
0.070
0.074
0.078
0.083
0.091
0.094
0.096
0.104
0.122
0.126
0.135
0.148
0.161
0.168
0.184
0.202
0.239
0.257
0.293
0.319
0.344
0.371
0.399
0.433
S
Point Taper Lengthc
For Short Screws
For Long Screws
Max
Min
Max
Min
0.062
0.045
0.080
0.062
0.055
0.039
0.070
0.055
0.073
0.052
0.094
0.073
0.062
0.045
0.080
0.062
0.088
0.062
0.112
0.088
0.073
0.052
0.094
0.073
0.088
0.062
0.112
0.088
0.080
0.057
0.102
0.080
0.109
0.078
0.141
0.109
0.088
0.062
0.112
0.088
0.109
0.078
0.141
0.109
0.097
0.069
0.125
0.097
0.146
0.104
0.188
0.146
0.109
0.078
0.141
0.109
0.146
0.104
0.188
0.146
0.125
0.089
0.161
0.125
0.175
0.125
0.225
0.175
0.125
0.089
0.161
0.125
0.194
0.139
0.250
0.194
0.146
0.104
0.188
0.146
0.219
0.156
0.281
0.219
0.146
0.104
0.188
0.146
0.250
0.179
0.321
0.250
0.175
0.125
0.225
0.175
0.269
0.192
0.346
0.269
0.175
0.125
0.225
0.175
L
Determinant Lengths for
Point Taperc
90° Heads Csk Heads
5⁄
32
1⁄
8
3⁄
16
5⁄
32
7⁄
32
3⁄
16
7⁄
32
3⁄
16
1⁄
4
7⁄
32
1⁄
4
7⁄
32
11⁄
32
1⁄
4
11⁄
32
5⁄
16
13⁄
32
5⁄
16
15⁄
32
11⁄
32
1⁄
2
11⁄
32
19⁄
32
13⁄
32
5⁄
8
13⁄
32
3⁄
16
3⁄
16
7⁄
32
3⁄
16
1⁄
4
7⁄
32
9⁄
32
1⁄
4
5⁄
16
9⁄
32
11⁄
32
5⁄
16
7⁄
16
11⁄
32
7⁄
16
13⁄
32
17⁄
32
13⁄
32
19⁄
32
15⁄
32
11⁄
16
1⁄
2
3⁄
4
9⁄
16
25⁄
32
9⁄
16
Minimum Practical
90° Heads Csk Heads
5⁄
32
1⁄
8
5⁄
32
5⁄
32
3⁄
16
5⁄
32
3⁄
16
3⁄
16
1⁄
4
3⁄
16
1⁄
4
7⁄
32
5⁄
16
1⁄
4
5⁄
16
9⁄
32
3⁄
8
9⁄
32
7⁄
16
5⁄
16
15⁄
32
5⁄
16
9⁄
16
3⁄
8
19⁄
32
3⁄
8
3⁄
16
5⁄
32
7⁄
32
3⁄
16
1⁄
4
7⁄
32
1⁄
4
1⁄
4
5⁄
16
1⁄
4
5⁄
16
9⁄
32
13⁄
32
5⁄
16
13⁄
32
3⁄
8
1⁄
2
3⁄
8
9⁄
16
15⁄
32
5⁄
8
1⁄
2
23⁄
32
17⁄
32
3⁄
4
17⁄
32
a Where specifying nominal size in decimals, zeros preceding decimal and in the fourth decimal place shall be omitted.
b The tabulated values apply to screw blanks before roll threading.
c Screws of these nominal lengths and shorter shall have point taper length specified above for short screws. Longer lengths shall have point taper length specified for
long screws.
All dimensions are in inches. See Table 2 for thread diagrams.
Type “Type D“ otherwise designated “Type 1.“
Type “Type T“ otherwise designated “Type 23.”
Nominal
Sizea or Basic
Screw
Diameter
2 0.0860
2 0.0860
3 0.0990
3 0.0990
4 0.1120
4 0.1120
5 0.1250
5 0.1250
6 0.1380
6 0.1380
8 0.1640
8 0.1640
10 0.1900
10 0.1900
12 0.2160
12 0.2160
1⁄
4 0.2500
1⁄
4 0.2500
5⁄
16 0.3125
5⁄
16 0.3125
3⁄
8 0.3750
3⁄
8 0.3750
7⁄
16 0.4375
7⁄
16 0.4375
1⁄
2 0.5000
1⁄
2 0.5000
1647
Table 8. Approximate Hole Sizes for Type A Steel Thread Forming Screws
Screw
Size
4
6
7
8
Metal
Thickness
In Steel, Stainless Steel, Monel Metal, Brass, and Aluminum Sheet Metal
Hole Size
Hole Size
Pierced
Drilled
Metal
Pierced
Drilled
or
or Clean
Drill
Screw
Thickor
or Clean
Extruded
Punched
Size
Size
ness
Extruded
Punched
0.015
…
0.086
44
0.018
0.024
0.030
0.036
0.015
0.018
0.024
0.030
0.036
0.015
0.018
0.024
0.030
0.036
0.048
0.018
…
0.098
0.098
0.098
…
…
0.111
0.111
0.111
…
…
0.120
0.120
0.120
0.120
…
0.086
0.094
0.094
0.098
0.104
0.104
0.104
0.104
0.106
0.116
0.116
0.116
0.116
0.116
0.120
0.125
44
42
42
40
37
37
37
37
36
32
32
32
32
32
31
1⁄
8
8
10
12
14
0.024
0.136
0.125
0.030
0.036
0.048
0.018
0.024
0.030
0.036
0.048
0.024
0.030
0.036
0.048
0.024
0.030
0.036
0.048
0.136
0.136
0.136
…
0.157
0.157
0.157
0.157
…
0.185
0.185
0.185
…
0.209
0.209
0.209
0.125
0.125
0.128
0.136
0.136
0.136
0.136
0.149
0.161
0.161
0.161
0.161
0.185
0.189
0.191
0.196
In Plywood (Resin Impregnated)
Screw
Size
Hole
Size
Drill
Size
Min.
Mat'l
Thickness
4
6
7
8
10
12
14
0.098
0.110
0.128
0.140
0.170
0.189
0.228
40
35
30
28
18
12
1
0.188
0.188
0.250
0.250
0.312
0.312
0.438
Drill
Size
1⁄
8
1⁄
8
1⁄
8
30
29
29
29
29
25
20
20
20
20
13
12
11
9
In Asbestos Compositions
Penetration
in Blind Holes
Min.
Max.
0.250
0.250
0.312
0.312
0.375
0.375
0.500
0.750
0.750
0.750
0.750
1.000
1.000
1.000
Screw
Size
Hole
Size
Drill
Size
Min.
Mat'l
Thickness
4
6
7
8
10
12
14
0.094
0.106
0.125
0.136
0.161
0.185
0.213
42
36
1⁄
8
29
20
13
3
0.188
0.188
0.250
0.250
0.312
0.312
0.438
Penetration
in Blind Holes
Min.
Max.
0.250
0.250
0.312
0.312
0.375
0.375
0.500
0.750
0.750
0.750
0.750
1.000
1.000
1.000
Type A is not recommended, use Type AB.
See footnote at bottom of Table 9.
Table 9. Approximate Hole Sizes for Type C Steel Thread Forming Screws
Screw
Size
4–40
6–32
8–32
Metal
Thickness
Hole
Size
Drill
Size
0.037
0.048
0.062
0.075
0.105
0.134
0.037
0.048
0.062
0.075
0.105
0.094
0.094
0.096
0.100
0.102
0.102
0.113
0.116
0.116
0.122
0.125
42
42
41
39
38
38
33
32
32
3.1mm
1⁄
8
0.134
0.125
0.037
0.048
0.062
0.075
0.105
0.134
0.136
0.144
0.144
0.147
0.150
0.150
1⁄
8
29
27
27
26
25
25
Screw
Size
10-24
10–32
12–24
In Sheet Steel
Metal
ThickHole
ness
Size
Drill
Size
Screw
Size
Metal
Thickness
Hole
Size
Drill
Size
0.037
0.048
0.062
0.075
0.105
0.134
0.037
0.048
0.062
0.075
0.105
0.221
0.221
0.228
0.234
0.234
0.236
0.224
0.228
0.232
0.234
0.238
2
2
1
A
A
6mm
5.7mm
1
5.9mm
A
B
0.037
0.048
0.062
0.075
0.105
0.134
0.037
0.048
0.062
0.075
0.105
0.154
0.161
0.166
0.170
0.173
0.177
0.170
0.170
0.170
0.173
0.177
23
20
19
18
17
16
18
18
18
17
16
0.134
0.177
16
0.134
0.238
B
0.037
0.048
0.062
0.075
0.105
0.134
0.189
0.194
0.194
0.199
0.199
0.199
12
10
10
8
8
8
0.037
0.048
0.062
0.075
0.105
0.134
0.290
0.290
0.290
0.295
0.295
0.295
L
L
L
M
M
M
1⁄ –20
4
1⁄ –28
4
5⁄ –18
16
All dimensions are in inches except drill sizes. It may be necessary to vary the hole size to suit a
particular application.
Type C is not recommended for new designs.
1648
Table 10. Approximate Pierced or Extruded Hole Sizes for Types AB, B,
and BP Steel Thread Forming Screws
Screw
Size
Metal
Thickness
Pierced
or Extruded
Hole Size
0.015
0.018
0.024
0.030
0.036
0.015
0.018
0.024
0.030
0.036
0.018
0.086
0.086
0.098
0.098
0.098
0.111
0.111
0.111
0.111
0.111
0.120
0.024
0.030
0.036
0.048
0.024
0.030
0.036
0.086
0.086
0.086
0.086
0.111
0.111
0.111
Screw
Size
Pierced
or Extruded
Hole Size
Metal
Thickness
Screw
Size
Metal
Thickness
Pierced
or Extruded
Hole Size
0.030
0.036
0.048
0.024
0.030
0.036
0.048
0.030
0.036
0.048
…
0.157
0.157
0.157
0.185
0.185
0.185
0.185
0.209
0.209
0.209
…
0.036
0.048
0.024
0.030
0.036
0.048
…
0.136
0.136
0.157
0.157
0.157
0.157
…
In Steel, Stainless Steel, Monel Metal, and Brass Sheet Metal
4
6
7
0.024
0.030
0.036
0.048
0.018
0.024
0.030
0.036
0.048
0.018
0.024
7
8
10
0.120
0.120
0.120
0.120
0.136
0.136
0.136
0.136
0.136
0.157
0.157
10
12
1⁄
4
…
In Aluminum Alloy Sheet Metal
4
6
6
0.048
0.024
0.030
0.036
0.048
0.024
0.030
7
8
0.111
0.120
0.120
0.120
0.120
0.136
0.136
8
10
…
All dimensions are in inches except whole number screw and drill sizes.
Since conditions differ widely, it may be necessary to vary the hole size to suit a particular application.
Table 11. Drilled Hole Sizes for Types AB, B, and BP Steel Thread Forming Screws
Screw
Size
Hole
Size
Drill
Size
Min.
Mat'l
Thickness
Penetration
in Blind
Holes
Min.
Max.
Screw
Size
Hole
Size
2
4
6
0.073
0.100
0.125
7
8
10
12
1⁄
4
0.136
0.144
0.173
0.194
0.228
2
4
6
7
8
10
12
1⁄
4
2
4
6
7
49
39
1⁄
8
29
27
17
10
1
47
42
31
30
Min.
Mat'l
Thickness
Penetration
in Blind
Holes
Min.
Max.
0.125
0.188
0.188
0.188
0.250
0.250
0.500
0.625
0.625
2
4
6
0.076
0.101
0.120
48
38
31
0.125
0.188
0.188
0.188
0.250
0.250
0.500
0.625
0.625
0.188
0.188
0.250
0.312
0.312
0.250
0.250
0.312
0.375
0.375
0.750
0.750
1.000
1.000
1.000
7
8
10
12
1⁄
4
0.136
0.147
0.166
0.196
0.228
29
26
19
9
1
0.250
0.312
0.312
0.312
0.438
0.312
0.375
0.375
0.375
0.500
0.750
0.750
1.000
1.000
1.000
…
…
…
…
…
…
…
…
2
4
6
7
8
10
12
1⁄
4
0.078
0.100
0.128
0.136
0.150
0.177
0.199
0.234
In Aluminum, Magnesium, Zinc, Brass,
and Bronze Castingsa
0.078
47
…
0.125
0.104
37
…
0.188
0.128
30
…
0.250
0.144
27
…
0.250
0.152
24
…
0.250
0.177
16
…
0.250
0.199
8
…
0.281
15⁄
0.234
…
0.312
64
0.078
0.094
0.120
0.128
Drill
Size
In Phenol Formaldehyde Plasticsa
47
39
30
29
25
16
8
15⁄
64
…
…
…
…
…
…
…
…
0.188
0.250
0.250
0.250
0.312
0.312
0.375
0.375
…
…
…
…
…
…
…
…
In Cellulose Acetate and Nitrate, and Acrylic and Styrene Resinsa
…
0.188
…
8
0.144
27
…
0.250
…
10
0.170
18
…
0.250
…
12
0.191
11
1⁄
…
0.250
…
0.221
2
4
…
…
…
…
0.312
0.312
0.375
0.375
…
…
…
…
a Data below apply to Types B and BP only.
All dimensions are in inches except whole number screw and drill sizes.
Since conditions differ widely, it may be necessary to vary the hole size to suit a particular application.
1649
Table 12a. Approximate Drilled or Clean-Punched Hole Sizes for Types AB, B, and
BP Steel Thread Forming Screws
Screw
Size
Metal
Thickness
Hole
Size
0.015
0.018
0.024
0.030
0.036
0.048
0.060
0.015
0.018
0.024
0.030
0.036
0.048
0.060
0.075
0.015
0.018
0.024
0.030
0.036
0.048
0.060
0.075
0.105
0.064
0.064
0.067
0.070
0.073
0.073
0.076
0.086
0.086
0.089
0.094
0.094
0.096
0.100
0.102
0.104
0.104
0.106
0.106
0.110
0.111
0.116
0.120
0.128
52
52
51
50
49
49
48
44
44
43
42
42
41
39
38
37
37
36
36
35
34
32
31
30
0.024
0.030
0.036
0.048
0.060
0.030
0.036
0.048
0.060
0.075
0.105
0.030
0.036
0.048
0.060
0.75
0.105
0.128
to
250
0.030
0.036
0.048
0.064
0.064
0.064
0.067
0.070
0.086
0.086
0.086
0.089
0.089
0.094
0.104
0.104
0.104
0.106
0.110
0.111
52
52
52
51
50
44
44
44
43
43
42
37
37
37
36
35
34
Drill
Size
Screw
Size
Metal
Thickness
Hole
Size
Drill
Size
Screw
Size
Metal
Thickness
Hole
Size
Drill
Size
0.125
0.135
0.164
0.024
0.030
0.036
0.048
0.060
0.075
0.105
0.125
0.135
0.164
0.030
0.036
0.048
0.060
0.075
0.105
0.125
0.135
0.164
0.187
0.194
0.170
0.170
0.173
0.166
0.166
0.166
0.170
0.177
0.182
0.185
0.196
0.196
0.201
0.194a
0.194a
0.194a
0.199a
0.204a
0.209
0.228
0.228
0.234
0.234
0.234
18
18
17
19
19
19
18
16
14
13
9
9
7
10a
10a
10a
8a
6a
4
1
1
15⁄
64
15⁄
64
15⁄
64
0.164
0.200
to
0.375
0.048
0.060
0.075
0.105
0.125
0.135
0.164
0.200
to
0.375
0.060
0.075
0.105
0.125
0.135
0.164
0.187
0.194
0.200
to
0.375
0.159
21
0.166
19
0.161
0.166
0.173
0.180
0.182
0.182
0.189
20
19
17
15
14
14
12
0.196
9
0.199
0.201
0.204
0.209
0.209
0.213
0.213
0.221
8
7
6
4
4
3
3
2
228
1
2
4
6
2
4
6
7
120
31
0.113
0.113
0.116
33
33
32
7
8
10
0.018
0.024
0.030
0.036
0.048
0.060
0.075
0.105
0.024
0.030
0.036
0.048
0.060
0.075
0.105
0.125
0.135
0.024
0.030
0.036
0.048
0.060
0.075
0.105
0.116
0.116
0.116
0.116
0.120
0.128
0.136
0.140
0.125
0.125
0.125
0.128
0.136
0.140
0.150
0.150
0.152
0.144
0.144
0.147
0.152a
0.152a
0.157
0.161
32
32
32
32
31
30
29
28
1⁄
8
1⁄
8
1⁄
8
30
29
28
25
25
24
27
27
26
24a
24a
22
20
0.060
0.120
31
0.075
0.128
30
0.105
0.136
29
7
0.128
to
0.136
29
0.250
0.030
0.116
32
0.036
0.120
31
0.048
0.128
30
0.060
0.136
29
0.075
0.140
28
0.105
0.147
26
8
0.125
0.147
26
0.135
0.149
25
0.162
to
0.152
24
0.375
0.036
0.144
27
0.048
0.144
27
0.060
0.144
27
0.075
0.147
26
10
0.105
0.147
26
0.125
0.154
23
0.135
0.154
23
10
12
1⁄
4
10
12
1⁄
4
a For Types B and BP only; for Type AB see concluded Table 12b following.
Since conditions differ widely, it may be necessary to vary the hole size to suit a particular application. Hole sizes for metal thicknesses above 0.075 inch are for Types B and BP only.
1650
Table 12b. Supplementary Data for Types AB Thread Forming Screws in Steel,
Stainless Steel, Monel Metal, and Brass Sheet Metal
Screw
Size
Metal
Thickness
Hole
Size
10
0.018
0.144
27
10
0.048
0.149
25
10
0.060
0.154
23
…
…
…
…
Drill
Size
Screw
Size
Metal
Thickness
Hole
Size
Drill
Size
Screw
Size
Metal
Thickness
Hole
Size
Drill
Size
0.048
0.205
5
0.060
0.228
1
0.075
0.232
5.9 mm
…
…
…
1⁄
4
1⁄
4
1⁄
4
1⁄
4
0.018
0.196
9
0.024
0.196
9
0.030
0.196
9
1⁄
4
1⁄
4
1⁄
4
0.036
0.196
9
…
All dimensions are in inches except numbered screw and drill sizes.
Table 13. Approximate Hole Sizes for Types D, F, G, and T Steel
Thread Cutting Screws in Sheet Metals
Steel
Screw
Size
2–56
3–48
4–40
5–40
6–32
8–32
Thickness
0.050
0.060
0.083
0.109
0.125
0.140
0.050
0.060
0.083
0.109
0.125
0.140
0.187
0.050
0.060
0.083
0.109
0.125
0.140
0.187
0.050
0.060
0.083
0.109
0.125
0.140
0.187
0.250
0.050
0.060
0.083
0.109
0.125
0.140
0.187
0.250
0.050
0.060
0.083
0.109
0.125
0.140
Hole
Size
0.073
0.073
0.073
0.073
0.076
0.076
0.081
0.081
0.082
0.086
0.086
0.086
0.089
0.089
0.089
0.094
0.096
0.098
0.098
0.102
0.106
0.106
0.106
0.106
0.109
0.110
0.116
0.116
0.110
0.113
0.116
0.116
0.116
0.120
0.125
0.125
0.136
0.140
0.140
0.144
0.144
0.147
Drill
Size
49
49
49
49
48
48
46
46
45
44
44
44
43
43
43
42
41
40
40
38
36
36
36
36
7⁄
64
35
32
32
35
33
32
32
32
31
1⁄
8
1⁄
8
29
28
28
27
27
26
Aluminum Alloy
Hole
Drill
Size
Size
0.070
50
0.073
49
0.073
49
0.073
49
0.073
49
0.073
49
5⁄
0.078
64
0.081
46
0.082
45
0.082
45
0.082
45
0.086
44
0.086
44
0.089
43
0.089
43
0.089
43
0.094
42
0.094
42
3⁄
0.094
32
0.098
40
0.102
38
0.102
38
0.104
37
0.104
37
0.106
36
0.106
36
0.110
35
0.113
33
7⁄
0.109
64
7⁄
0.109
64
0.111
34
0.113
33
0.116
32
0.116
32
0.120
31
1⁄
0.125
8
0.136
29
0.136
29
0.136
29
0.140
28
0.140
28
0.144
27
Steel
Screw
Size
8–32
10–24
10–32
12–24
1⁄ –20
4
Thickness
0.187
0.250
0.312
0.050
0.060
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.050
0.060
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.060
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.500
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.500
Hole
Size
0.150
0.150
0.150
0.152
0.154
0.161
0.161
0.166
0.170
0.173
0.173
0.173
0.173
0.159
0.166
0.166
0.170
0.170
0.170
0.177
0.177
0.177
0.177
0.180
0.182
0.188
0.191
0.191
0.199
0.199
0.199
0.199
0.199
0.213
0.219
0.221
0.221
0.228
0.228
0.228
0.228
0.228
Drill
Size
25
25
25
24
23
20
20
19
18
17
17
17
17
21
19
19
18
18
18
16
16
16
16
15
14
3⁄
16
11
11
8
8
8
8
8
3
7⁄
32
2
2
1
1
1
1
1
Aluminum Alloy
Hole
Drill
Size
Size
0.147
26
0.150
25
0.150
25
0.150
25
0.152
24
0.154
23
0.157
22
0.159
21
0.161
20
0.166
19
11⁄
0.172
64
0.173
17
0.173
17
0.161
20
0.161
20
0.161
20
0.166
19
0.166
19
0.166
19
11⁄
0.172
64
0.177
16
0.177
16
0.177
16
0.177
16
0.180
15
0.182
14
0.185
13
3⁄
0.188
16
0.191
11
0.199
8
0.199
8
0.199
8
0.199
8
0.206
5
0.209
4
0.213
3
0.213
3
0.221
2
0.228
1
0.228
1
0.228
1
0.228
1
1651
Table 13. (Continued) Approximate Hole Sizes for Types D, F, G, and T Steel
Thread Cutting Screws in Sheet Metals
Steel
Screw
Size
1⁄ –28
4
5⁄ –18
16
5⁄ –24
16
Thickness
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.500
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.500
0.109
0.125
0.140
Hole
Size
0.221
0.228
0.228
0.234
0.234
0.234
0.234
0.234
0.234
0.277
0.277
0.281
0.290
0.290
0.290
0.290
0.290
0.290
0.290
0.290
Drill
Size
2
1
1
A
15⁄
64
15⁄
64
15⁄
64
15⁄
64
15⁄
64
J
J
9⁄
32
L
L
L
L
L
L
L
L
Aluminum Alloy
Hole
Drill
Size
Size
7⁄
0.219
32
0.221
2
0.221
2
0.221
2
0.228
1
15⁄
0.234
64
15⁄
0.234
64
15
⁄64
0.234
15⁄
0.234
64
0.266
H
0.272
I
0.272
I
0.281
K
0.290
L
0.290
L
0.290
L
0.290
L
0.281
K
9
⁄32
0.281
9⁄
0.281
32
Steel
Screw
Size
5⁄ –24
16
3⁄ –16
8
3⁄ –24
8
Thickness
0.187
0.250
0.312
0.375
0.500
Hole
Size
0.295
0.295
0.295
0.295
0.295
Drill
Size
M
M
M
M
M
0.125
0.140
0.187
0.250
0.312
0.375
0.500
0.125
0.140
0.187
0.250
0.312
0.375
0.500
…
0.339
0.339
0.348
0.358
0.358
0.358
0.358
0.348
0.348
0.358
0.358
0.358
0.358
0.358
…
R
R
S
T
T
T
T
S
S
T
T
T
T
T
…
Aluminum Alloy
Hole
Drill
Size
Size
0.290
L
0.295
M
0.295
M
0.295
M
0.295
M
0.328
0.332
0.339
0.348
0.348
0.348
0.348
0.344
0.344
0.348
0.358
0.358
0.358
0.358
…
21⁄
64
Q
R
S
S
S
S
11⁄
32
11⁄
32
S
T
T
T
T
…
All dimensions are in inches except numbered drill and screw sizes. It may be necessary to vary the
hole size to suit a particular application.
Table 14. Approximate Hole Sizes for Types D, F, G, and T
Steel Thread Cutting Screws in Cast Metals and Plastics
Screw
Size
2–56
3–48
4–40
5–40
Thickness
Cast Iron
Hole
Drill
Size
Size
Zinc and
Aluminuma
Hole
Drill
Size
Size
0.050
0.076
48
0.073
49
0.083
0.113
33
0.106
36
0.060
0.076
48
0.073
49
0.109
0.113
33
0.110
35
0.083
0.076
48
0.076
48
0.125
0.116
32
0.110
35
0.109
0.078
5⁄
64
0.076
48
0.140
0.116
32
0.110
35
0.125
0.078
5⁄
64
0.076
48
0.187
0.116
32
0.111
34
0.140
0.078
5⁄
64
0.076
48
0.250
0.116
32
0.113
33
0.050
0.089
43
0.082
45
0.050
0.120
31
0.116
32
0.060
0.089
43
0.082
45
0.060
0.120
31
0.120
31
0.083
0.089
43
0.082
45
0.083
0.125
1⁄
8
0.120
31
0.109
0.089
43
0.086
44
0.109
0.125
1⁄
8
0.120
31
0.125
0.089
43
0.089
43
0.125
0.125
1⁄
8
0.120
31
0.140
0.094
42
0.089
43
0.140
0.125
1⁄
8
0.120
31
0.187
0.094
42
0.089
43
0.187
0.128
30
0.120
31
0.050
0.100
39
0.090
41
0.250
0.128
30
0.120
31
0.060
0.100
39
0.096
41
0.050
0.147
26
0.144
27
0.083
0.102
38
0.096
41
0.060
0.150
25
0.144
27
0.109
0.102
38
0.096
41
0.083
0.150
25
0.144
27
0.125
0.102
38
0.100
39
0.109
0.150
25
0.144
27
0.140
0.102
38
0.100
39
0.125
0.150
25
0.147
26
0.187
0.104
37
0.100
39
0.140
0.150
25
0.147
26
0.050
0.111
34
0.106
36
0.187
0.154
23
0.147
26
0.060
0.111
34
0.106
36
0.250
0.154
23
0.150
25
0.312
0.154
23
0.150
25
Screw
Size
5–40
6–32
8–32
Thickness
Cast Iron
Hole
Drill
Size
Size
Zinc and
Aluminuma
Hole
Drill
Size
Size
1652
Table 14. (Continued) Approximate Hole Sizes for Types D, F, G, and T
Steel Thread Cutting Screws in Cast Metals and Plastics
Screw
Size
10–24
10–32
12–24
1⁄ –20
4
Thickness
0.050
0.060
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
Cast Iron
Hole
Drill
Size
Size
0.170
18
0.170
18
11⁄
0.172
64
0.173
17
0.173
17
0.173
17
0.177
16
0.177
16
0.177
16
0.177
16
Zinc and
Aluminuma
Hole
Drill
Size
Size
0.161
20
0.166
19
0.166
19
0.166
19
0.166
19
0.166
19
0.170
18
0.170
18
11⁄
0.172
64
11⁄
0.172
64
0.050
0.060
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.060
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.500
0.173
0.173
0.177
0.177
0.177
0.177
0.180
0.180
0.180
0.180
0.196
0.199
0.199
0.199
0.199
0.203
0.204
0.204
0.204
0.204
17
17
16
16
16
16
15
15
15
15
9
8
8
8
8
13⁄
64
6
6
6
6
0.170
0.170
0.172
0.172
0.172
0.172
0.172
0.173
0.173
0.177
0.189
0.191
0.191
0.191
0.194
0.194
0.196
0.196
0.199
0.199
18
18
11⁄
64
11⁄
64
11⁄
64
11⁄
64
11⁄
64
17
17
16
12
11
11
11
10
10
9
9
8
8
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.500
0.228
0.228
0.228
0.228
0.234
0.234
0.234
0.234
0.234
1
1
1
1
15⁄
64
15⁄
64
15⁄
64
15⁄
64
15⁄
64
0.219
0.219
0.221
0.221
0.221
0.228
0.228
0.228
0.228
7⁄
32
7⁄
32
Screw
Size
1⁄ –28
4
5⁄ –18
16
5⁄ –24
16
3⁄ –16
8
2
2
2
1
1
1
1
3⁄ –24
8
Thickness
0.083
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.500
Cast Iron
Hole
Drill
Size
Size
0.234
A
15⁄
0.234
64
15⁄
0.234
64
15⁄
0.234
64
0.238
B
0.238
B
0.238
B
0.238
B
0.238
B
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.500
0.290
0.290
0.290
0.295
0.295
0.295
0.295
0.295
L
L
L
M
M
M
M
M
Zinc and
Aluminuma
Hole
Drill
Size
Size
0.228
1
0.228
1
0.228
1
0.228
1
0.228
1
0.234
A
0.234
A
15⁄
0.234
64
15⁄
0.234
64
0.277
J
0.281
K
0.281
K
9⁄
0.281
32
9⁄
0.281
32
0.290
L
0.290
L
0.290
L
0.109
0.125
0.140
0.187
0.250
0.312
0.375
0.500
0.125
0.140
0.187
0.250
0.312
0.375
0.295
0.295
0.295
0.302
0.302
0.302
0.302
0.302
0.348
0.348
0.348
0.348
0.348
0.348
M
M
M
N
N
N
N
N
S
S
S
S
S
S
0.290
0.290
0.290
0.290
0.290
0.295
0.295
0.295
0.339
0.339
0.339
0.344
0.344
0.348
L
L
L
L
L
M
M
M
R
R
R
11⁄
32
11⁄
32
S
0.500
0.348
S
0.348
S
0.125
0.140
0.187
0.250
0.312
0.375
0.500
0.358
0.358
0.358
0.358
0.358
0.358
0.358
T
T
T
T
T
T
T
0.348
0.348
0.348
0.358
0.358
0.358
0.358
S
S
S
T
T
T
T
a Die Castings
Phenol
Formaldehydea
Depth of Penetration
Min
Max
Screw
Size
Hole
Size
Drill
Size
2–56
3–48
4–40
5–40
6–32
8–32
10–24
10–32
1⁄ –20
4
0.078
0.089
0.098
0.113
0.116
0.144
0.161
0.166
0.228
5⁄
64
43
40
33
32
27
20
19
1
0.219
0.219
0.250
0.250
0.250
0.312
0.375
0.375
0.375
0.375
0.375
0.312
0.438
0.312
0.500
0.500
0.500
0.625
Hole
Size
0.076
0.086
0.093
0.110
0.116
0.144
0.161
0.166
0.228
Cellulose Acetate, Cellulose Nitrate,
Acrylic Resin, and Styrene Resina
Drill
Size
Min
Max
48
44
42
35
32
27
20
19
1
0.219
0.219
0.250
0.250
0.250
0.312
0.375
0.375
0.375
a Plastics
For footnotes see Table 13.
0.375
0.375
0.312
0.438
0.312
0.500
0.500
0.500
1.000
1653
Table 15. Approximate Hole Sizes for Types BF and BT
Steel Thread Cutting Screws in Cast Metals
In Die Cast Zinc and Aluminum
Screw
Size
2
3
4
5
6
8
Thickness
Hole
Size
Drill
Size
0.060
0.083
0.109
0.125
0.140
0.073
0.073
0.076
0.076
0.076
49
49
48
48
48
0.060
0.086
0.083
0.109
0.125
0.140
0.188
0.109
0.125
0.140
0.188
0.250
0.109
0.125
0.140
0.188
0.250
0.125
0.140
0.188
0.250
Screw
Size
Thickness
Hole
Size
Drill
Size
0.125
0.140
0.188
0.250
0.312
0.166
0.166
0.166
0.170
0.172
19
19
19
18
11⁄
64
44
0.375
0.172
11⁄
64
0.086
0.086
0.086
0.089
0.089
0.098
0.100
0.100
0.100
0.102
0.111
0.111
0.113
0.113
0.116
0.120
0.120
0.120
0.125
44
44
44
43
43
40
39
39
39
38
34
34
33
33
32
31
31
31
0.191
0.191
0.191
0.196
0.196
0.196
0.221
0.221
0.221
0.228
0.228
0.228
0.281
0.281
0.281
0.281
0.290
0.290
0.344
11
11
11
9
9
9
2
2
2
1
1
1
K
K
K
K
L
L
1⁄
8
0.125
0.140
0.188
0.250
0.312
0.375
0.125
0.140
0.188
0.250
0.312
0.375
0.125
0.140
0.188
0.250
0.312
0.375
0.125
11⁄
32
0.312
0.125
1⁄
8
0.140
0.344
11⁄
32
0.125
0.149
25
0.188
0.344
11⁄
32
0.140
0.149
25
0.250
0.344
11⁄
32
0.188
0.250
0.312
0.149
0.152
0.152
25
24
24
0.312
0.375
…
0.348
0.348
…
S
S
…
10
12
1⁄
4
5⁄
16
3⁄
8
All dimensions are in inches except numbered drill and screw sizes. It may be necessary to vary the
hole size to suit a particular application.
Table 16. Approximate Hole Size for Types BF and BT
Steel Thread Cutting Screws in Plastics
Phenol
Formaldehyde
Hole
Size
Drill
Size
2
0.078
3
4
Cellulose Acetate, Cellulose Nitrate,
Acrylic Resin and Styrene Resin
Min
Max
Hole
Size
Drill
Size
Min
Max
5⁄
64
0.094
0.250
0.076
48
0.094
0.250
0.089
43
0.125
0.312
0.089
43
0.125
0.312
0.104
37
0.125
0.312
0.100
39
0.125
0.312
5
0.116
32
0.188
0.375
0.113
33
0.188
0.375
6
0.125
1⁄
8
0.188
0.375
0.120
31
0.188
0.375
Screw
Size
8
0.147
26
0.250
0.500
0.144
27
0.250
0.500
10
0.170
18
0.312
0.625
0.166
19
0.312
0.625
12
0.194
10
0.375
0.625
0.189
12
0.375
0.625
1⁄
4
0.228
1
0.375
0.750
0.221
2
0.375
0.750
For footnotes see above table.
1654
THREAD INSERTS
Table 17. Approximate Hole Sizes for Type U Hardened Steel Metallic Drive Screws
Screw
Size
Hole
Size
Drill
Size
In Ferrous and Non-Ferrous Castings, Sheet Metals, Plastics,
Plywood (Resin-Impregnated) and Fiber
Screw
Hole
Drill
Screw
Size
Size
Size
Size
Hole
Size
Drill
Size
00
0
2
4
.052
.067
.086
.104
55
51
44
37
.191
.221
.295
.358
11
2
M
T
6
7
8
10
.120
.136
.144
.161
31
29
27
20
12
14
5⁄
16
3⁄
8
All dimensions are in inches except whole number screw and drill sizes and letter drill sizes.
Table 18. ANSI Standard Torsional Strength Requirements for Tapping Screws
ANSI B18.6.4-1981 (R1991)
Nom.
Screw
Size
2
3
4
5
6
7
8
10
12
14
Type
A
4
9
12
18
24
30
39
48
83
125
Types
AB,B,BF,
BP,andBT
4
9
13
18
24
30
39
56
88
…
Types C, D,
F, G, and T
Coarse
Fine
Thread
Thread
5
6
9
10
13
15
18
20
23
27
…
…
42
47
56
74
93
108
…
…
NomScrew
Size
1⁄
4
16
18
5⁄
16
20
24
3⁄
8
7⁄
16
1⁄
2
…
Type
A
…
152
196
…
250
492
…
…
…
…
Types
AB, B,
BF, BP,
and BT
142
…
…
290
…
…
590
620
1020
…
Types C, D,
F, G, and T
Coarse
Fine
Thread
Thread
140
179
…
…
…
…
306
370
…
…
…
…
560
710
700
820
1075
1285
…
…
Torsional strength data are in pound-inches.
Self-tapping Thread Inserts.—Self-tapping screw thread inserts are essentially hard
bushings with internal and external threads. The internal threads conform to Unified and
American standard classes 2B and 3B, depending on the type of insert used. The external
thread has cutting edges on the end that provide the self-tapping feature. These inserts may
be used in magnesium, aluminum, cast iron, zinc, plastics, and other materials. Self-tapping inserts are made of case-hardened carbon steel, stainless steel, and brass, the brass
type being designed specifically for installation in wood.
Screw Thread Inserts.—Screw thread inserts are helically formed coils of diamondshaped stainless steel or phosphor bronze wire that screw into a threaded hole to form a
mating internal thread for a screw or stud. These inserts provide a convenient means of
repairing stripped-out threads and are also used to provide stronger threads in soft materials such as aluminum, zinc die castings, wood, magnesium, etc. than can be obtained by
direct tapping of the base metal involved.
According to the Heli-Coil Corp., conventional design practice in specifying boss diameters or edge distances can usually be applied since the major diameter of a hole tapped to
receive a thread insert is not much larger than the major diameter of thread the insert provides.
Screw thread inserts are available in thread sizes from 4–40 to 11⁄2–6 inch National and
Unified Coarse Thread Series and in 6–40 to 11⁄2–12 sizes in the fine-thread series. When
used in conjunction with appropriate taps and gages, screw thread inserts will meet
requirements of 2, 2B, 3, and 3B thread classes.
ANSI Standard Metric Thread Forming and Thread Cutting Tapping Screws.—
Table 1 shows the various types of metric thread forming and thread cutting screw
threads covered by the standard ANSI/ASME B18.6.5M-1986. The designations of the
American National Standards Institute are shown.
METRIC SELF-THREADING SCREWS
1655
Table 1. ANSI Standard Threads and Points for Metric Thread Forming and Thread
Cutting Tapping Screws ANSI/ASME B18.6.5M-1986
DETAIL OF THREAD FORM
TYPE BF
DETAIL OF THREAD FORM
TYPE BT
TYPE F
TYPE D
TYPE T
See Tables 3 and 4 for thread data.
Thread Forming Tapping Screws: These types are generally for application in materials
where large internal stresses are permissible or desirable, to increase resistance to loosening. These screws have the following descriptions and applications:
1656
Type AB: Spaced thread screw with gimlet point primarily intended for use in thin metal,
resin impregnated plywood, and asbestos compositions.
Type B: Spaced thread screw with a blunt point that has tapered entering threads with
unfinished crests and same pitches as Type AB. Used for thin metal, nonferrous castings,
resin impregnated plywood, certain resilient plastics, and asbestos compositions.
Thread Cutting Tapping Screws: These screws are generally for application in materials
where disruptive internal stresses are undesirable or where excessive driving torques are
encountered with thread forming tapping screws. These screws have the following
descriptions and applications:
Types BF and BT: Spaced threads with blunt point and tapered entering threads having
unfinished crests, as on Type B, with one or more cutting edges or chip cavities, intended
for use in plastics, asbestos compositions, and other similar materials.
Types D, F, and T: Tapping screws with threads of machine screw diameter-pitch combinations (metric coarse thread series) approximating a 60 degree basic thread form (not
necessarily conforming to any standard thread profile) with a blunt point and tapered entering threads with unfinished crests and having one or more cutting edges and chip cavities,
intended for use in materials such as aluminum, zinc, and lead die castings; steel sheets and
shapes; cast iron; brass; and plastics.
ANSI Standard Head Types for Metric Thread Forming and Cutting Tapping
Screws.—The head types covered by ANSI/ASME B18.6.5M-1986 include those commonly applicable to metric tapping screws and are described as follows:
Flat Countersunk Head: The flat countersunk head has a flat top surface and a conical
bearing surface with a head angle of 90 to 92 degrees.
Oval Countersunk Head: The oval countersunk head has a rounded top surface and a
conical bearing surface with a head angle of 90 to 92 degrees.
Pan Head: The slotted pan head has a flat top surface rounding into cylindrical sides and
a flat bearing surface. The recessed pan head has a rounded top surface blending into cylindrical sides and a flat bearing surface.
Hex Head: The hex head has a flat or indented top surface, six flat sides, and a flat bearing surface.
Hex Flange Head: The hex flange head has a flat or indented top surface and six flat
sides formed integrally with a frustroconical or slightly rounded (convex) flange that
projects beyond the sides and provides a flat bearing surface.
Method of Designation.—Metric tapping screws are designated with the following data,
preferably in the sequence shown: Nominal size; thread pitch; nominal length; thread and
point type; product name, including head style and driving provision; material; and protective finish, if required.
Examples:
6.3 × 1.8 × 30 Type AB, Slotted Pan Head Tapping Screw, Steel, Zinc Plated
6 × 1 × 20 Type T, Type 1A Cross Recessed Pan Head Tapping Screw, Corrosion Resistant Steel
4.2 × 1.4 × 13 Type BF, Type 1 Cross Recessed Oval Countersunk Head Tapping Screw,
Steel, Chromium Plated
10 × 1.5 × 40 Type D, Hex Flange Head Tapping Screw, Steel
1657
Table 2. Recommended Nominal Screw Lengths for Metric Tapping Screws
Nominal Screw Size for Types AB, B, BF, and BT
2.2
-
2.9
Nominal
Screw
Length
2
2.5
4
PH
PH
5
PH
PH
6
A
3.5
4.2
4.8
5.5
6.3
8
9.5
-
6
8
10
Nominal Screw Size for Types D, F, and T
3
3.5
4
5
A
PH
8
A
A
A
PH
PH
10
A
A
A
A
A
13
A
A
A
A
A
A
A
PH
A
A
A
A
A
A
A
PH
20
A
A
A
A
A
A
25
A
A
A
A
A
A
A
30
A
A
A
A
A
35
A
A
A
A
A
A
A
16
PH
40
PH
A
A
45
A
A
50
A
A
55
A
60
A
Table 3. ANSI Standard Thread and Point Dimensions for Types AB and B Metric
Thread Forming Tapping Screws ANSI/ASME B18.6.5M-1986
D1
D2
D3
Y
L
Z
Point
Taper
Length
Type Bc
Min. Practical
Nominal Screw
Lengthd
Basic
Screw
Diameter
Basic
Thread
Pitch
Refe
Refe
Max
Min
Max
Min
Max
Min
Max
2.2 × 0.8
2.184
0.79
2.24
2.10
1.63
1.52
1.47
1.37
1.6
1.2
2.0
4
6
4
5
2.9 × 1
2.845
1.06
2.90
2.76
2.18
2.08
2.01
1.88
2.1
1.6
2.6
6
7
5
7
3.5 × 1.3
3.505
1.27
3.53
3.35
2.64
2.51
2.41
2.26
2.5
1.9
3.2
7
9
6
8
4.2 × 1.4
4.166
1.41
4.22
4.04
3.10
2.95
2.84
2.69
2.8
2.1
3.7
8
10
7
10
4.8 × 1.6
4.826
1.59
4.80
4.62
3.58
3.43
3.30
3.12
3.2
2.4
4.3
9
12
8
11
5.5 × 1.8
5.486
1.81
5.46
5.28
4.17
3.99
3.86
3.68
3.6
2.7
5.0
11
14
9
12
6.3 × 1.8
6.350
1.81
6.25
6.03
4.88
4.70
4.55
4.34
3.6
2.7
6.0
12
16
10
13
8 × 2.1
7.938
2.12
8.00
7.78
6.20
5.99
5.84
5.64
4.2
3.2
7.5
16
20
12
17
9.5 × 2.1
9.525
2.12
9.65
9.43
7.85
7.59
7.44
7.24
4.2
3.2
8.0
19
24
14
19
Thread
Major
Diameter
Thread
Minor
Diameter
Point
Diameterb
Min
Point
Length
Factor
TypeAB
Reff
Type AB
Type B
Note
7
Note
8
Note
7
Note
8
Nominal
Screw
Size and
Thread
Pitcha
a The
body diameter (unthreaded portion) is not less than the minimum minor diameter nor greater
than the maximum major diameter of the thread.
b The tabulated values shall apply to screw blanks prior to roll threading.
c The tabulated maximum limits are equal to approximately two times the thread pitch.
d Lengths shown are theoretical minimums and are intended to assist the user in the selection of
appropriate short screw lengths. Refer to Table 2 for recommended diameter-length combinations.
e Basic screw diameter and basic thread pitch shall be used for calculation purposes wherever these
factors appear in formulations for dimensions.
f The minimum effective grip length on Type AB tapping screws shall be determined by subtracting
the point length factor from the minimum screw length.
All dimensions are in millimeters. See Table 1 for thread diagrams.
7 Pan, hex, and hex flange heads.
8 Flat and oval countersunk heads.
1658
Table 4. ANSI Standard Thread and Point Dimensions for Types BF, BT, D, F, and T
Metric Thread Cutting Tapping Screws ANSI/ASME B18.6.5M-1986
Types BF and BT
D1
D2
D3
Y
L
Minimal Practical
Nominal Screw Lengthc
Point
Diametera
Point
Taper
Length
Type Bb
Basic
Screw
Diameter
Basic
Thread
Pitch
Refd
Refd
Max
Min
Max
Min
Max
Min
Max
2.2 × 0.8
2.184
0.79
2.24
2.10
1.63
1.52
1.47
1.37
1.6
2.9 × 1
2.845
1.06
2.90
2.76
2.18
2.08
2.01
1.88
2.1
3.5 × 1.3
3.505
1.27
3.53
3.35
2.64
2.51
2.41
2.26
4.2 × 1.4
4.166
1.41
4.22
4.04
3.10
2.95
2.84
4.8 × 1.6
4.826
1.59
4.80
4.62
3.58
3.43
3.30
5.5 × 1.8
5.486
1.81
5.46
5.28
4.17
3.99
3.86
6.3 × 1.8
6.350
1.81
6.25
6.03
4.88
4.70
8 × 2.1
7.938
2.12
8.00
7.78
6.20
9.5 × 2.1
9.525
2.12
9.65
9.43
7.85
Nominal
Screw
Size
and
Thread
Pitch
Thread
Major
Diameter
Thread
Minor
Diameter
Min
Pan, Hex
and Hex
Flange
Heads
Flat and
Oval
Csunk
Heads
1.2
4
5
1.6
5
7
2.5
1.9
6
8
2.69
2.8
2.1
7
10
3.12
3.2
2.4
8
11
3.68
3.6
2.7
9
12
4.55
4.34
3.6
2.7
10
13
5.99
5.84
5.64
4.2
3.2
12
17
7.59
7.44
7.24
4.2
3.2
14
19
a The tabulated values apply to screw blanks prior to roll threading.
b The tabulated maximum limits are equal to approximately two times the thread pitch.
c Lengths shown are theoretical minimums and are intended to assist in the selection of appropriate
short screw lengths. See Table 2 for recommended length-diameter combinations. For Types D, F, and
T, shorter screws are available with the point length reduced to the limits tabulated for short screws.
d Basic screw diameter and basic thread pitch are used for calculation purposes whenever these factors appear in formulations for dimensions.
Types D, F, T
D1
Nominal
Screw
Size
and
Thread
Pitch
D3
Thread
Major
Diameter
DS
Y
L
Point Taper Length
Minimum Practical
Nominal Screw Lengthc
For
Short
Screws
For
Long
Screwsb
Flat and
Oval
Csunk
Heads
5
Max
Min
Max
Min
Min
Max
Min
Max
Min
Pan, Hex
and Hex
Flange
Heads
2 × 0.4
2.00
1.88
1.45
1.39
1.65
1.4
1.0
1.8
1.4
4
2.5 × 0.45
2.50
2.37
1.88
1.82
2.12
1.6
1.1
2.0
1.6
4
6
3 × 0.5
3.00
2.87
2.32
2.26
2.58
1.8
1.3
2.3
1.8
5
6
3.5 × 0.6
3.50
3.35
2.68
2.60
3.00
2.1
1.5
2.7
2.1
5
8
4 × 0.7
4.00
3.83
3.07
2.97
3.43
2.5
1.8
3.2
2.5
6
9
5 × 0.8
5.00
4.82
3.94
3.84
4.36
2.8
2.0
3.6
2.8
7
10
Point
Diametera
Body
Diametera
6×1
6.00
5.79
4.69
4.55
5.21
3.5
2.5
4.5
3.5
9
12
8 × 1.25
8.00
7.76
6.40
6.24
7.04
4.4
3.1
5.6
4.4
11
16
10 × 1.5
10.00
9.73
8.08
7.88
8.86
5.3
3.8
6.8
5.3
13
18
a Minimum
limits for body diameter (unthreaded portion) are tabulated for convenient reference.
For Types BF and BT, the body diameter is not less than the minimum minor diameter nor greater than
the maximum major diameter of the thread.
b Long screws are screws of nominal lengths equal to or longer than those listed under L.
All dimensions are in millimeters. See Table 1 for thread diagrams.
Material and Heat Treatment.—Tapping screws are normally fabricated from carbon
steel and are suitably processed to meet the performance and test requirements outlined in
the standard, B18.6.5M. Tapping screws may also be made from corrosion resistant steel,
Monel, brass, and aluminum alloys. The materials, properties, and performance characteristics applicable to such screws should be mutually agreed upon between the manufacturer
and the purchaser.
1659
Table 5. Clearance Holes for Metric Tapping Screws
ANSI/ASME B18.6.5M-1986 Appendix
Nominal
Screw Size
and
Thread Pitch
2.2 ×0.8
2.9 ×1
3.5 ×1.3
4.2 ×1.4
4.8 ×1.6
5.5 ×1.8
6.3×1.8
8 ×2.1
9.5 ×2.1
Normal
Clearance
Close
Loose
(Preferred)b
Clearanceb
Clearanceb
Types AB, B, BF, and BT
2.40
2.60
2.80
3.10
3.30
3.50
3.70
3.90
4.20
4.50
4.70
5.00
5.10
5.30
5.60
5.90
6.10
6.50
6.70
6.90
7.30
8.40
9.00
10.00
10.00
10.50
11.50
Nominal
Screw Size
and
Thread Pitch
2 ×0.4
2.5 ×0.45
3 ×0.5
3.5 ×0.6
4 ×0.7
5 ×0.8
6 ×1
8 ×1.25
10 ×1.5
Normal
Clearance
Close
Loose
(Preferred)b
Clearanceb
Clearanceb
Types D, F, and T
2.20
2.40
2.60
2.70
2.90
3.10
3.20
3.40
3.60
3.70
3.90
4.20
4.30
4.50
4.80
5.30
5.50
5.80
6.40
6.60
7.00
8.40
9.00
10.00
10.50
11.00
12.00
a The values given in this table are minimum limits. The recommended plus tolerances are as follows: for clearance hole diameters over 1.70 to and including 5.80 mm, plus 0.12, 0.20, and 0.30 mm
for close, normal, and loose clearances, respectively; over 5.80 to and including 14.50 mm, plus 0.18,
0.30, and 0.45 mm for close, normal, and loose clearances, respectively.
b Normal clearance hole sizes are preferred. Close clearance hole sizes are for situations such as critical alignment of assembled components, wall thickness, or other limitations that necessitate the use
of a minimal hole. Countersinking or counterboring at the fastener entry side may be necessary for the
proper seating of the head. Loose clearance hole sizes are for applications where maximum adjustment capability between the components being assembled is necessary.
Approximate Installation Hole Sizes for Metric Tapping Screws.—The approximate
hole sizes given in Tables 7 through 9 provide general guidance in selecting holes for
installing the respective types of metric thread forming and thread cutting tapping screws
in various commonly used materials. Types AB, B, BF, and BT metric tapping screws are
covered in these tables; hole sizes for Types D, F, and T metric thread cutting tapping
screws are still under development.
Table 6. Approximate Pierced or Extruded Hole Sizes for Steel
Types AB and B Metric Thread Forming Tapping Screws
Nominal
Screw Size
andThread
Pitch
2.9 × 1
3.5 × 1.3
2.9 × 1
3.5 × 1.3
Metal
Thickness
Nominal
Nominal
Screw Size
Screw Size
andThread
andThread
Metal
Hole
Hole
Pitch
Pitch
Thickness
Size
Size
In Steel, Stainless Steel, Monel, and Brass Sheet Metal
0.38
0.46
0.61
0.76
0.91
0.38
0.46
0.61
0.76
0.91
2.18
2.18
2.49
2.49
2.49
2.82
2.82
2.82
2.82
2.82
0.61
0.76
0.91
1.22
0.61
0.76
2.18
2.18
2.18
2.18
2.82
2.82
0.46
0.61
0.76
0.91
1.22
0.46
0.61
4.8 × 1.6
0.76
0.91
1.22
In Aluminum Alloy
0.91
3.5 × 1.3
1.22
0.61
0.76
4.2 × 1.4
0.91
1.22
4.2 × 1.4
3.45
3.45
3.45
3.45
3.45
3.99
3.99
3.99
3.99
3.99
2.82
2.82
3.45
3.45
3.45
3.45
Metal
Thickness
Hole
Size
0.61
0.76
0.91
1.22
…
0.76
0.91
1.22
…
…
4.70
4.70
4.70
4.70
…
5.31
5.31
5.31
…
…
0.61
0.76
0.91
1.22
…
…
3.99
3.99
3.99
3.99
…
…
5.5 × 1.8
6.3 × 1.8
4.8 × 1.6
1660
Table 7. Approximate Drilled or Clean-Punched Hole Sizes for Steel Type AB Metric
Thread Forming Tapping Screws in Sheet Metal
Nominal
Screw
Size and
Thread
Pitch
Nominal
Screw
Size and
Thread
Pitch
Metal
Thickness
Hole
Size
0.38
1.63
52
0.61
2.69
36
0.46
1.63
52
0.76
2.69
36
0.61
1.70
51
0.91
2.79
0.76
1.78
50
1.22
0.91
1.85
49
1.22
1.85
49
1.52
1.93
48
Drill
Sizea
Metal
Thickness
Nominal
Screw
Size and
Thread
Pitch
Metal
Thickness
Hole
Size
Drill
Sizea
1.22
3.78
25
1.52
3.91
23
35
1.90
3.99
22
2.82
34
0.46
…
…
1.52
2.95
32
0.61
4.22
19
1.90
3.05
31
0.76
4.22
19
0.46
…
…
0.91
4.22
19
Hole
Size
Drill
Sizea
2.2 × 0.8
2.9 × 1
3.5 × 1.3
3.5 × 1.3
4.8 × 1.6
5.5 × 1.8
0.38
2.18
44
0.61
3.18
…
1.22
4.32
18
0.46
2.18
44
0.76
3.18
…
1.52
4.50
16
0.61
2.26
43
0.91
3.18
…
1.90
4.62
14
0.76
2.39
42
4.2 × 1.4
1.22
3.25
30
0.46
4.98
9
0.91
2.39
42
1.52
3.45
29
0.61
4.98
9
1.22
2.44
41
1.90
3.56
28
0.76
4.98
9
1.52
2.54
39
0.46
3.66
27
0.91
4.98
9
1.90
2.59
38
0.61
3.66
27
1.22
5.21
W
0.38
2.64
37
0.76
3.66
27
1.52
5.79
1
0.46
2.64
37
0.91
3.73
26
1.90
5.89
…
0.38
…
…
0.61
…
…
1.22
3.66
27
0.46
…
…
0.76
2.64
37
1.52
3.66
27
0.61
1.63
52
0.91
2.64
37
1.90
3.73
26
4.8 × 1.6
6.3 × 1.8
2.2 × 0.8
2.9 × 1
3.5 × 1.3
3.5 × 1.3
4.8 × 1.6
0.76
1.63
52
1.22
2.64
37
0.46
…
…
0.91
1.63
52
1.52
2.69
36
0.61
…
…
1.22
1.70
51
1.90
2.79
35
0.76
…
…
1.52
1.78
50
0.46
…
…
0.91
…
…
0.38
…
…
0.61
…
…
1.22
4.09
20
0.46
…
…
0.76
2.95
32
1.52
4.22
19
0.61
…
…
0.91
3.05
31
1.90
4.39
17
4.2 × 1.4
5.5 × 1.8
0.76
2.18
44
1.22
3.25
30
0.46
…
…
0.91
2.18
44
1.52
3.45
29
0.61
…
…
1.22
2.18
44
1.90
3.56
28
0.76
…
…
1.52
2.26
43
0.46
…
…
0.91
…
…
1.90
2.26
43
0.61
…
…
1.22
…
…
0.38
…
…
0.76
…
…
1.52
5.05
8
0.46
…
…
0.91
3.66
27
1.90
5.11
7
4.8 × 1.6
6.3 × 1.8
a Customary drill size references have been retained where the metric hole diameters are direct con-
versions of their decimal inch equivalents.
All dimensions are in millimeters except drill sizes.
1661
Table 8. Approximate Hole Sizes for Steel Type AB Metric Thread Forming
Tapping Screws in Plywoods and Asbestos
Nominal
Screw Size
and Thread
Pitch
Drill
Sizea
Hole
Size
Penetration in
Blind Holes
Min
Mat'l
Thickness
Min
Penetration in Blind
Holes
Drill
Sizea
Hole
Size
Max
Min Mat'l
Thickness
Min
Max
In Asbestors Compositions
2.2 ×0.8
1.85
49
3.18
4.78
12.70
1.93
48
3.18
4.78
2.9 ×1
2.54
39
4.78
6.35
15.88
2.57
38
4.78
6.35
15.88
3.5 ×1.3
3.18
…
4.78
6.35
15.88
3.05
31
4.78
6.35
15.88
4.2 ×1.4
3.66
27
4.78
6.35
19.05
3.73
26
7.92
9.52
19.05
4.8 ×1.6
4.39
17
6.35
7.92
25.40
4.22
19
7.92
9.52
25.40
5.5 ×1.8
4.93
10
7.92
9.52
25.40
4.98
9
7.92
9.52
25.40
6.3 ×1.8
5.79
1
7.92
9.52
25.40
5.79
1
11.13
12.70
25.40
12.70
Table 9. Approximate Hole Sizes for Steel Type B Metric Thread Forming Tapping
Screws in Plywoods, Asbestos, and Plastics
Nominal
Screw
Size and
Thread Pitch
Drill
Sizea
Hole
Size
Min
Mat'l
Thickness
Penetration in
Blind Holes
Min
Max
Nominal
Screw Size
and Thread
Pitch
Hole
Size
Drill
Sizea
Min
Mat'l
Thickness
Penetration in
Blind Holes
Min
Max
2.2 × 0.8
1.85
49
3.18
4.78
12.70
4.8 × 1.6
4.39
17
6.35
7.92
25.40
2.9 × 1
2.54
39
4.78
6.35
15.88
5.5 × 1.8
4.93
10
7.92
9.52
25.40
1
7.92
9.52
25.40
…
…
…
3.5 × 1.3
3.18
…
4.78
6.35
15.88
6.3 × 1.8
5.79
4.2 × 1.4
3.66
27
4.78
6.35
19.05
…
…
…
Nominal Screw
Size and Thread Pitch
Hole
Size
Drill
Sizea
Penetration in Blind Holes
Min Mat'l
Thickness
Min
Max
4.78
6.35
6.35
9.52
9.52
9.52
12.70
12.70
15.88
15.88
19.05
25.40
25.40
25.40
2.2 × 0.8
2.9 × 1
3.5 × 1.3
4.2 × 1.4
4.8 × 1.6
5.5 × 1.8
6.3 × 1.8
Nominal Screw
Size and Thread
Pitch
1.93
2.57
3.05
3.73
4.22
4.98
5.79
Hole
Size
Drill
Sizea
48
38
31
26
19
9
1
Min Penetration
in Blind Holes
3.18
4.78
4.78
7.92
7.92
7.92
11.13
Hole
Size
In Phenol Formaldehyde
2.2 × 0.8
2.9 × 1
3.5 × 1.3
4.2 × 1.4
4.8 × 1.6
5.5 × 1.8
6.3 × 1.8
1.98
2.54
3.25
3.81
4.50
5.05
5.94
47
39
30
25
16
8
…
Drill
Sizea
Min Penetration
in Blind Holes
In Cellulose Acetate & Nitrate,
Acrylic and Styrene Resins
4.78
6.35
6.35
7.92
7.92
9.52
9.52
1.98
2.39
3.05
3.66
4.32
4.85
5.61
47
42
32
27
18
11
2
4.78
6.35
6.35
7.92
7.92
9.52
9.52
1662
Table 10. Approximate Drilled or Clean-Punched Hole Sizes for Steel Type B Metric
Thread Forming Tapping Screws in Sheet Metal and Cast Metals
Nominal
Screw
Size and
Thread
Pitch
2.2 × 0.8
2.9 × 1
3.5 × 1.3
2.2 × 0.8
2.9 × 1
3.5 × 1.3
Nominal
Nominal
Screw
Screw
Size and
Metal
Size and
Drill
Drill
Thread
ThickHole
Thread
Sizea
Pitch
ness
Size
Sizea
Pitch
Metal
Thickness
Hole
Size
0.38
0.46
0.61
0.76
0.91
1.22
1.52
0.38
0.46
0.61
0.76
0.91
1.22
1.52
1.90
0.38
0.46
0.61
0.76
0.91
1.22
1.52
1.63
1.63
1.70
1.78
1.85
1.85
1.93
2.18
2.18
2.26
2.39
2.39
2.44
2.54
2.59
2.64
2.64
2.69
2.69
2.79
2.82
2.95
52
52
51
50
49
49
48
44
44
43
42
42
41
39
38
37
37
36
36
35
34
32
0.61
0.76
0.91
1.22
1.52
0.76
0.91
1.22
1.52
1.90
2.67
0.76
0.91
1.22
1.52
1.90
2.67
3.25
to
6.25
1.63
1.63
1.63
1.70
1.78
2.18
2.18
2.18
2.26
2.26
2.39
2.64
2.64
2.64
2.69
2.79
2.82
52
52
52
51
50
44
44
44
43
43
42
37
37
37
36
35
34
3.05
31
1.90
2.67
0.61
0.76
0.91
1.22
1.52
1.90
2.67
3.18
3.43
0.61
0.76
0.91
1.22
1.52
1.90
2.67
3.18
3.43
4.17
3.5 × 1.3
4.2 × 1.4
4.8 × 1.6
3.05
3.25
3.18
3.18
3.18
3.25
3.45
3.56
3.81
3.81
3.86
3.66
3.66
3.73
3.86
3.86
3.99
4.09
4.32
4.32
4.39
31
30
…
…
…
30
29
28
25
25
24
27
27
26
24
24
22
20
18
18
17
0.76
2.95
32
0.91
3.05
31
1.22
3.25
30
1.52
3.45
29
1.90
3.56
28
4.2 × 1.4
2.67
3.73
26
3.18
3.73
26
3.43
3.78
25
4.11
to
9.52
3.86
24
0.91
3.66
27
1.22
3.66
27
1.52
3.66
27
1.90
3.73
26
2.67
3.73
26
3.18
3.91
23
4.8 × 1.6
3.43
3.91
23
4.17
4.04
21
5.08
to
9.52
4.22
19
5.5 × 1.8
6.3 × 1.8
5.5 × 1.8
6.3 × 1.8
Metal
Thickness
Hole
Size
Drill
Sizea
0.61
0.76
0.91
1.22
1.52
1.90
2.67
3.18
3.43
4.17
0.76
0.91
1.22
1.52
1.90
2.67
3.18
3.43
4.17
4.75
4.93
4.22
4.22
4.22
4.32
4.50
4.62
4.70
4.98
4.98
5.11
4.93
4.93
4.93
5.05
5.18
5.31
5.79
5.79
5.94
5.94
5.94
19
19
19
18
16
14
13
9
9
7
10
10
10
8
6
4
1
1
…
…
…
1.22
1.52
1.90
2.67
3.18
3.43
4.17
5.08
to
9.52
1.52
1.90
2.67
3.18
3.43
4.17
4.75
4.93
5.08
to
9.52
4.09
4.22
4.39
4.57
4.62
4.62
4.80
20
19
17
15
14
14
12
4.98
5.05
5.11
5.18
5.31
5.31
5.41
5.41
5.61
9
8
7
6
4
4
3
3
2
5.79
1
a Customary drill size references have been retained where the metric hole diameters are direct conversions of their decimal inch equivalents.
Nominal
Screw Size
and Thread
Pitch
Hole
Size
2.2 × 0.8
2.9 × 1
3.5 × 1.3
4.2 × 1.4
1.98
2.64
3.25
3.86
In Aluminum, Magnesium, Zinc, Brass, and Bronze Cast Metals
Nominal
Screw Size
Min
Drill
and Thread
Hole
Penetration
a
Size
Pitch
Size
in Blind Holes
47
37
30
24
3.18
4.78
6.35
6.35
4.8 × 1.6
5.5 × 1.8
6.3 × 1.8
…
4.50
5.05
5.94
…
Drill
Sizea
Min
Penetration
in Blind Holes
16
8
4
…
6.35
7.14
7.92
…
All dimensions are in millimeters, except drill sizes.
1663
Table 11. Approximate Hole Sizes for Steel Types BF and BT
Metric Thread Cutting Tapping Screws for Cast Metals and Plastics
Nominal
Screw Size and
Thread Pitch
2.2 × 0.8
2.9 × 1
4.8 × 1.6
5.5 × 1.8
6.3 × 1.8
Material
Thickness
Hole
Size
1.52
2.11
2.77
3.18
3.56
2.77
3.18
3.56
4.78
6.35
3.18
3.56
4.78
6.35
7.92
9.52
3.18
3.56
4.78
6.35
7.92
9.52
3.18
3.56
4.78
1.85
1.85
1.93
1.93
1.93
2.49
2.54
2.54
2.54
2.59
4.22
4.22
4.22
4.32
4.37
4.37
4.85
4.85
4.85
4.98
4.98
4.98
5.61
5.61
5.61
Nominal Screw
Size and Thread Pitch
2.2 × 0.8
2.9 × 1.0
3.5 × 1.3
4.2 × 1.4
4.8 × 1.6
5.5 × 1.8
6.3 × 1.8
2.2 × 0.8
2.9 × 1.0
3.5 × 1.3
4.2 × 1.4
4.8 × 1.6
5.5 × 1.8
6.3 × 1.8
Nominal
Drill
Screw Size and
Sizea
Thread Pitch
In Die Cast Zinc and Aluminum
Hole
Size
49
49
48
48
48
40
39
39
39
38
19
19
19
18
…
…
11
11
11
9
9
9
2
2
2
3.5 × 1.3
4.2 × 1.4
6.3 × 1.8
8 × 2.1
9.5 × 2.1
Drill
Sizea
In Phenol Formaldehyde
Material
Thickness
Drill
Sizea
Hole
Size
3.18
3.05
3.56
3.05
4.78
3.05
6.35
3.18
7.92
3.18
3.18
3.78
3.56
3.78
4.78
3.78
6.35
3.86
7.92
3.86
6.35
5.79
7.92
5.79
9.52
5.79
3.18
7.14
3.56
7.14
4.78
7.14
6.35
7.14
7.92
7.37
9.52
7.37
3.18
8.74
3.56
8.74
4.78
8.74
6.35
8.74
7.92
8.84
9.52
8.84
Min
Max
1.98
…
2.39
2.64
37
3.18
3.18
…
4.78
3.73
26
6.35
4.32
18
7.92
4.93
10
9.52
5.79
1
9.52
In Cellulose Acetate and Nitrate, Acrylic and Styrene Resins
1.93
48
2.39
2.54
39
3.18
3.05
31
4.78
3.66
27
6.35
4.22
19
7.92
4.80
12
9.52
5.61
2
9.52
31
31
31
…
…
25
25
25
24
24
1
1
1
K
K
K
K
L
L
…
…
…
…
S
S
6.35
7.92
9.52
12.70
15.88
15.88
19.05
6.35
7.92
9.52
12.70
15.88
15.88
19.05
a Customary drill size references have been retained where the metric hole sizes are direct conversions of their decimal inch equivalents.
The finish (plating or coating) on metric tapping screws and the material composition
and hardness of the mating component are factors that affect assembly torques in individual applications. Although the recommended installation hole sizes given in Tables 7
through 9 were based on the use of plain unfinished carbon steel metric tapping screws,
experience has shown that the specified holes are also suitable for screws having most
types of commercial finishes. However, owing to various finishes providing different
degrees of lubricity, some adjustment of installation torques may be necessary to suit individual applications. Also, where exceptionally heavy finishes are involved or screws are to
be assembled into materials of higher hardness, some deviation from the specified hole
sizes may be required to provide optimum assembly. The necessity and extent of such
deviations can best be determined by experiment in the particular assembly environment.
1664
T-SLOTS, BOLTS, AND NUTS
Table 1. American National Standard T-Slots ANSI/ASME B5.1M-1985 (R1998)
T-SLOTS
Nominal
T-Bolt Sizea
inch
mm
0.250
0.312
0.375
0.500
0.625
0.750
1.000
1.250
1.500
4
5
6
8
10
12
16
20
24
30
36
42
48
Width of
Throat A1b
inch
mm
0.282
0.344
0.438
0.562
0.688
0.812
1.062
1.312
1.562
5
6
8
10
12
14
18
22
28
36
42
48
54
Width of Headspace B1
Depth of Headspace C1
inch
inch
min
0.500
0.594
0.719
0.906
1.188
1.375
1.750
2.125
2.562
mm
max
min
max
0.562
0.656
0.781
0.969
1.250
1.469
1.844
2.219
2.656
10
11
14.5
16
19
23
30
37
46
56
68
80
90
11
12.5
16
18
21
25
32
40
50
60
72
85
95
min
0.203
0.234
0.297
0.359
0.453
0.594
0.781
1.031
1.281
Depth of Throat D1
mm
inch
max
min
max
0.234
0.266
0.328
0.391
0.484
0.625
0.828
1.094
1.344
3
5
7
7
8
9
12
16
20
25
32
36
40
3.5
6
8
8
9
11
14
18
22
28
35
40
44
min
0.125
0.156
0.219
0.312
0.438
0.562
0.750
1.000
1.250
Rounding or Breaking of Cornersc
mm
inch
max
min
max
0.375
0.438
0.562
0.688
0.875
1.062
1.250
1.562
1.938
4.5
5
7
9
11
12
16
20
26
33
39
44
50
7
8
11
14
17
19
24
29
36
46
53
59
66
R1
max
0.02
0.02
0.02
0.02
0.03
0.03
0.03
0.03
0.03
W1
max
0.02
0.03
0.03
0.03
0.03
0.03
0.06
0.06
0.06
mm
U1
max
R1
max
W1
max
U1
max
0.03
0.03
0.03
0.03
0.05
0.05
0.05
0.05
0.05
0.5
0.5
0.5
0.5
0.5
0.5
0.8
0.8
0.8
0.8
0.8
1.5
1.5
0.8
0.8
0.8
0.8
0.8
0.8
0.8
0.8
1.5
1.5
1.5
2.5
2.5
0.8
0.8
0.8
0.8
0.8
0.8
1.3
1.3
1.3
1.3
1.3
2
2
a Width of tongue (tenon) to be used with the above T-Slots will be found in the complete standard, B5.1M.
b Throat dimensions are basic. When slots are intended to be used for holding only, tolerances can be 0.0 + 0.010 inch or H12 Metric (ISO/R286); when intended for
location, tolerance can be 0.0 + 0.001 inch or H8 Metric (see page 670).
c Corners of T-Slots may be square or may be rounded or broken to the indicated maximum dimensions at the manufacturer's option.
For the dimensions of tongue seats, inserted tongues, and solid tongues refer to the complete standard, B5.1M.
T-BOLTS, SLOTS, NUTS, AND TONGUES
Suggested Approximate Dimensions
For Rounding Or Breaking Of Corners
Basic Dimensions
Table 2. American National Standard T-Bolts ANSI/ASME B5.1M-1985 (R1998)
T-BOLTS
Width Across Flats
B2
inch
metric
inch
UNC-2A
ISOd
max
min
max
0.250–20
0.312–18
0.375–16
0.500–13
0.625–11
0.750–10
1.000–8
1.250–7
1.500–6
M4
M5
M6
M8
M10
M12
M16
M20
M24
M30
M36
M42
M48
0.469
0.562
0.688
0.875
1.125
1.312
1.688
2.062
2.500
0.438
0.531
0.656
0.844
1.094
1.281
1.656
2.031
2.469
9
10
13
15
18
22
28
34
43
53
64
75
85
Width Across
Corners
mm
mm
min
max
max
max
min
max
8.5
9.5
12
14
17
21
27
33
42
52
63
74
84
0.663
0.796
0.972
1.238
1.591
1.856
2.387
2.917
3.536
12.7
14.1
18.4
21.2
25.5
31.1
39.6
48.1
60.8
75
90.5
106.1
120.2
0.156
0.188
0.250
0.312
0.406
0.531
0.688
0.938
1.188
0.141
0.172
0.234
0.297
0.391
0.500
0.656
0.906
1.156
2.5
4
6
6
7
8
10
14
18
23
28
32
36
a For inch tolerances for thread diameters of bolts or studs and for threads see page
R2
Height C2
inch
inch
mm
W2
inch
mm
inch
mm
min
max
max
max
max
2.1
3.6
5.6
5.6
6.6
7.6
9.6
13.2
17.2
22.2
27.2
30.5
34.5
0.02
0.02
0.02
0.02
0.03
0.03
0.03
0.03
0.03
0.3
0.3
0.5
0.5
0.5
0.5
0.8
0.8
0.8
0.8
0.8
1
1
0.03
0.03
0.03
0.06
0.06
0.06
0.06
0.06
0.06
0.5
0.5
0.8
0.8
0.8
1.5
1.5
1.5
1.5
1.5
1.5
2
2
Rounding of Cornersc
Bolt Head Dimensions
Nominal T-Bolt
Size and Thread
A2ab
1736.
b T-slots to be used with these bolts will be found in Table 1.
d Metric thread grade and tolerance position is 5g 6g (see page
1790).
1665
c Corners of T-bolts may be square or may be rounded or broken to the indicated maximum dimensions at the manufacturer's option.
1666
Table 3. American National Standard T-Nuts ANSI/ASME B5.1M-1985 (R1998)
T-NUTS
0.250
inch
mm
max
mm
min
max
min
inch
mm
UNC-3B
ISOd
Width of Nut
B3
inch
max
mm
min
Rounding of Corners
Height of Nut
C3
max min
inch
max
mm
min
max
min
Total Thickness
Including
Tonguec K3
inch
mm
Length
of Nutc
L3
inch
R3
mm
W3
inch
mm
inch
mm
max
max
max
max
4
…
…
…
…
…
…
…
…
…
…
…
5
…
…
…
…
…
…
…
…
…
…
…
…
…
6
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
0.312
8
0.330
0.320
8.7
8.5
0.250–20
M6
0.562
0.531
15
14
0.188
0.172
6
5.6
0.281
9
0.562
18
0.02
0.5
0.03
0.8
0.375
10
0.418
0.408
11
10.75
0.312–18
M8
0.688
0.656
18
17
0.250
0.234
7
6.6
0.375
10.5
0.688
20
0.02
0.5
0.03
0.8
0.500
12
0.543
0.533
13.5
13.25
0.375–1
6M10
0.875
0.844
22
21
0.312
0.297
8
7.6
0.531
12
0.875
23
0.02
0.5
0.06
1.5
0.625
16
0.668
0.658
17.25
17
0.500–13
M12
1.125
1.094
28
27
0.406
0.391
10
9.6
0.625
15
1.125
27
0.03
0.8
0.06
1.5
0.750
20
0.783
0.773
20.5
20.25
0.625–11
M16
1.312
1.281
34
33
0.531
0.500
14
13.2
0.781
21
1.312
35
0.03
0.8
0.06
1.5
1.000
24
1.033
1.018
26.5
26
0.750–10
M20
1.688
1.656
43
42
0.688
0.656
18
17.2
1.000
27
1.688
46
0.03
0.8
0.06
1.5
1.250
30
1.273
1.258
33
32.5
1.000–8
M24
2.062
2.031
53
52
0.938
0.906
23
22.2
1.312
34
2.062
53
0.03
0.8
0.06
1.5
1.500
36
1.523
1.508
39.25
38.75
1.250–7
M30
2.500
2.469
64
63
1.188
1.156
28
27.2
1.625
42
2.500
65
0.03
0.8
0.06
1.5
42
46.75
46.25
M36
75
74
32
30.5
48
75
1
2
48
52.5
51.75
M42
85
84
36
34.5
54
85
1
2
a T-slot dimensions to fit the above nuts will be found in Table 1.
b For tolerances of inch threads see page
1736.
c No tolerances are given for “Total Thickness” or “Nut Length” as they need not be held to close limits.
d Metric tapped thread grade and tolerance position is 5H (see page
1790).
inch
Tap for Studb
E3
Width of Tongue
A3
Nominal
T-Bolt
Sizea
COTTER AND CLEVIS PINS
1667
PINS AND STUDS
Dowel-Pins.—Dowel-pins are used either to retain parts in a fixed position or to preserve
alignment. Under normal conditions a properly fitted dowel-pin is subjected solely to
shearing strain, and this strain occurs only at the junction of the surfaces of the two parts
which are being held by the dowel-pin. It is seldom necessary to use more than two dowelpins for holding two pieces together and frequently one is sufficient. For parts that have to
be taken apart frequently, and where driving out of the dowel-pins would tend to wear the
holes, and also for very accurately constructed tools and gages that have to be taken apart,
or that require to be kept in absolute alignment, the taper dowel-pin is preferable. The taper
dowel-pin is most commonly used for average machine work, but the straight type is given
the preference on tool and gage work, except where extreme accuracy is required, or where
the tool or gage is to be subjected to rough handling.
The size of the dowel-pin is governed by its application. For locating nests, gage plates,
etc., pins from 1⁄8 to 3⁄16 inch in diameter are satisfactory. For locating dies, the diameter of
the dowel-pin should never be less than 1⁄4 inch; the general rule is to use dowel-pins of the
same size as the screws used in fastening the work. The length of the dowel-pin should be
about one and one-half to two times its diameter in each plate or part to be doweled.
When hardened cylindrical dowel-pins are inserted in soft parts, ream the hole about
0.001 inch smaller than the dowel-pin. If the doweled parts are hardened, grind (or lap) the
hole 0.0002 to 0.0003 inch under size. The hole should be ground or lapped straight, that is,
without taper or “bell-mouth.”
American National Standard Cotter Pins ANSI B18.8.1-1972 (R1994)
L
C
D
C
A
B
L
A
B
Plane of Contact with Gage
Dia.
Aa &
Width B
Max.
Wire
Width
B
Min.
Head
Dia.
C
Min.
Prong
Length
D
Min.
Hole
Size
3⁄
16
0.176
0.137
0.38
0.09
0.203
7⁄
32
0.207
0.161
0.44
0.10
0.234
0.078
1⁄
4
0.225
0.176
0.50
0.11
0.266
0.04
0.094
5⁄
16
0.280
0.220
0.62
0.14
0.312
0.19
0.04
0.109
3⁄
8
0.335
0.263
0.75
0.16
0.375
0.080
0.22
0.05
0.125
7⁄
16
0.406
0.320
0.88
0.20
0.438
0.120
0.093
0.25
0.06
0.141
1⁄
2
0.473
0.373
1.00
0.23
0.500
9⁄
64
0.134
0.104
0.28
0.06
0.156
5⁄
8
0.598
0.472
1.25
0.30
0.625
5⁄
32
0.150
0.116
0.31
0.07
0.172
3⁄
4
0.723
0.572
1.50
0.36
0.750
Nom.
Size
Dia.
Aa &
Width B
Max.
Wire
Width
B
Min.
Head
Dia.
C
Min.
Prong
Length
D
Min.
Hole
Size
1⁄
32
0.032
0.022
0.06
0.01
0.047
3⁄
64
0.048
0.035
0.09
0.02
0.062
1⁄
16
0.060
0.044
0.12
0.03
5⁄
64
0.076
0.057
0.16
3⁄
32
0.090
0.069
7⁄
64
0.104
1⁄
8
Nom.
Size
are: −0.004 inch for the 1⁄32- to 3⁄16-inch sizes, incl.; −0.005 inch for the 7⁄32- to 5⁄16-inch
sizes, incl.; −0.006 inch for the 3⁄8- to 1⁄2-inch sizes, incl.; and −0.008 inch for the 5⁄8- and 3⁄4-inch sizes.
Note: Tolerances for length are: up to 1 inch ± 0.030 inch, over 1 inch ±0.060 inch.
a Tolerances
;
;
1668
DOWEL PINS
American National Standard Clevis Pins ANSI B18.8.1-1972 (R1994)
Radius
1
G
+ 0.02
– 0.00
B
A
H
D
F
45
L
0.005
0.015
Optional
Nom.Size
(Basic
Pin Dia.)
C
R
E Dia. (Break Corners)
Shank
Dia.A
Max
Head
Dia.B
Max.a
Head
Hgt.C
Max.b
Head
Chamfer
D Nom.c
Hole
Dia.E
Max.d
Point
Dia.F
Max.e
Pin
Lgth.G
Basicf
Head to
HoleCenter
H Max.g
Max.
Min.
Cotter
Pin Size
for Hole
Point Length L
3⁄
16
0.186
0.32
0.07
0.02
0.088
0.15
0.58
0.504
0.055
0.035
1⁄
16
1⁄
4
0.248
0.38
0.10
0.03
0.088
0.21
0.77
0.692
0.055
0.035
1⁄
16
5⁄
16
0.311
0.44
0.10
0.03
0.119
0.26
0.94
0.832
0.071
0.049
3⁄
32
3⁄
8
0.373
0.51
0.13
0.03
0.119
0.33
1.06
0.958
0.071
0.049
3⁄
32
7⁄
16
0.436
0.57
0.16
0.04
0.119
0.39
1.19
1.082
0.071
0.049
3⁄
32
1⁄
2
0.496
0.63
0.16
0.04
0.151
0.44
1.36
1.223
0.089
0.063
1⁄
8
5⁄
8
0.621
0.82
0.21
0.06
0.151
0.56
1.61
1.473
0.089
0.063
1⁄
8
3⁄
4
0.746
0.94
0.26
0.07
0.182
0.68
1.91
1.739
0.110
0.076
5⁄
32
7⁄
8
0.871
1.04
0.32
0.09
0.182
0.80
2.16
1.989
0.110
0.076
5⁄
32
0.996
1.19
0.35
0.10
0.182
0.93
2.41
2.239
0.110
0.076
5⁄
32
a Tolerance is −0.05 inch.
b Tolerance is −0.02 inch.
c Tolerance is ±0.01 inch.
d Tolerance is −0.015 inch.
e Tolerance is −0.01 inch.
f Lengths tabulated are intended for use with standard clevises, without spacers. When other lengths
are required, it is recommended that they be limited wherever possible to nominal lengths in 0.06-inch
increments.
g Tolerance is −0.020 inch.
British Standard for Metric Series Dowel Pins.—Steel parallel dowel pins specified in
British Standard 1804:Part 2:1968 are divided into three grades which provide different
degrees of pin accuracy.
Grade 1 is a precision ground pin made from En 32A or En 32B low carbon steel (BS
970) or from high carbon steel to BS 1407 or BS 1423. Pins below 4 mm diameter are
unhardened. Those of 4 mm diameter and above are hardened to a minimum of 750 HV 30
in accordance with BS 427, but if they are made from steels to BS 1407 or BS 1423 then the
hardness shall be within the range 600 to 700 HV 30, in accordance with BS 427. The values of other hardness scales may be used in accordance with BS 860.
Grade 2 is a ground pin made from any of the steels used for Grade 1. The pins are normally supplied unhardened, unless a different condition is agreed on between the purchaser and supplier.
Grade 3 pins are made from En 1A free cutting steel (BS 970) and are supplied with a
machined, bright rolled or drawn finish. They are normally supplied unhardened unless a
different condition is agreed on between the purchaser and supplier.
Pins of any grade may be made from different steels in accordance with BS 970, by
mutual agreement between the purchaser and manufacturer. If steels other than those in the
DOWEL PINS
1669
standard range are used, the hardness of the pins shall also be decided on by mutual agreement between purchaser and supplier. As shown in the illustration at the head of the
accompanying table, one end of each pin is chamfered to provide a lead. The other end may
be similarly chamfered, or domed.
British Standard Parallel Steel Dowel Pins — Metric Series BS 1804: Part 2: 1968
Nom.
Length L,
mm
4
6
8
10
12
16
20
25
30
35
40
45
50
60
70
80
90
100
110
120
Nominal Diameter D, mm
4
5
6
8
Chamfer a max, mm
0.6
0.75
0.9
1.2
Standard Sizes
1
1.5
2
2.5
3
0.3
0.3
0.3
0.4
0.45
10
12
16
20
25
1.5
1.8
2.5
3
4
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
Limits of Tolerance on Diameter
Gradea
Tolerance Zone
Nom. Dia., mm
Over
To & Incl.
3
3
6
10
14
18
24
6
10
14
18
24
30
1
2
3
m5
h7
h11
+7
+2
+9
+12
+15
+15
+17
+17
+4
+6
+7
+7
+8
+8
Limits of Tolerance, 0.001 mm
0
−12b
0
0
0
0
0
0
−12
−15
−18
−18
−21
−21
0
−60
0
0
0
0
0
0
−75
−90
−110
−110
−130
−130
a The limits of tolerance for grades 1 and 2 dowel pins have been chosen to provide satisfactory
assembly when used in standard reamed holes (H7 and H8 tolerance zones). If the assembly is not satisfactory, refer to B.S. 1916: Part 1, Limits and Fits for Engineering, and select a different class of fit.
b This tolerance is larger than that given in BS 1916, and has been included because the use of a
closer tolerance would involve precision grinding by the manufacturer, which is uneconomic for a
grade 2 dowel pin.
The tolerance limits on the overall length of all grades of dowel pin up to and including 50 mm long
are +0.5, −0.0 mm, and for pins over 50 mm long are +0.8, −0.0 mm. The Standard specifies that the
roughness of the cylindrical surface of grades 1 and 2 dowel pins, when assessed in accordance with
BS 1134, shall not be greater than 0.4 µm CLA (16 CLA).
1670
Table 1. American National Standard Hardened Ground Machine Dowel Pins ANSI/ASME B18.8.2-1995
Pin Diameter, A
3⁄
32
1⁄
8
5⁄ d
32
3⁄
16
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
7⁄
8
1
Standard Series Pins
Point
Diameter, B
Oversize Series Pins
Crown
Height, C
Crown
Radius, R
Range of
Preferred
Lengths,b L
3⁄ –3⁄
16 4
…
Single Shear
Load, for Carbon
or Alloy Steel,
Calculated lb
Suggested
Hole Diameterc
Basic
Max
Min
Basic
Max
Min
Max
Min
Max
Min
0.0627
0.0783
0.0628
0.0784
0.0626
0.0782
0.0635
0.0791
0.0636
0.0792
0.0634
0.0790
0.058
0.074
0.048
0.064
0.020
0.026
0.008
0.010
Max
Min
400
620
0.0625
0.0781
0.0620
0.0776
0.0938
0.0940
0.0941
0.0939
0.0948
0.0949
0.0947
0.089
0.079
0.031
0.012
0.1250
0.1252
0.1253
0.1251
0.1260
0.1261
0.1259
0.120
0.110
0.041
0.016
5⁄ –1
16
3⁄ –2
8
1,600
0.1250
0.1245
0.1562
0.1564
0.1565
0.1563
0.1572
0.1573
0.1571
0.150
0.140
0.052
0.020
…
2,500
900
0.0937
0.1562
0.1557
0.1875
0.1877
0.1878
0.1876
0.1885
0.1886
0.1884
0.180
0.170
0.062
0.023
0.2500
0.2502
0.2503
0.2501
0.2510
0.2511
0.2509
0.240
0.230
0.083
0.031
0.3125
0.3127
0.3128
0.3126
0.3135
0.3136
0.3134
0.302
0.290
0.104
0.039
0.3750
0.3752
0.3753
0.3751
0.3760
0.3761
0.3759
0.365
0.350
0.125
0.047
0.4375
0.4377
0.4378
0.4376
0.4385
0.4386
0.4384
0.424
0.409
0.146
0.055
0.5000
0.5002
0.5003
0.5001
0.5010
0.5011
0.5009
0.486
0.471
0.167
0.063
0.6250
0.6252
0.6253
0.6251
0.6260
0.6261
0.6259
0.611
0.595
0.208
0.078
0.7500
0.7502
0.7503
0.7501
0.7510
0.7511
0.7509
0.735
0.715
0.250
0.094
0.8750
0.8752
0.8753
0.8751
0.8760
0.8761
0.8759
0.860
0.840
0.293
0.109
1.0000
1.0002
1.0003
1.0001
1.0010
1.0011
1.0009
0.980
0.960
0.333
0.125
1⁄ –2
2
1⁄ –21⁄
2
2
1⁄ –21⁄
2
2
1⁄ –3
2
7⁄ –3
8
3⁄ , 1–4
4
1
1 ⁄4–5
11⁄2–6
2,21⁄2–6
2,21⁄2–5,6
0.0932
3,600
0.1875
0.1870
6,400
0.2500
0.2495
10,000
0.3125
0.3120
14,350
0.3750
0.3745
19,550
0.4375
0.4370
25,500
0.5000
0.4995
39,900
0.6250
0.6245
57,000
0.7500
0.7495
78,000
0.8750
0.8745
102,000
1.0000
0.9995
a Where specifying nominal size as basic diameter, zeros preceding decimal and in the fourth decimal place are omitted.
b Lengths increase in 1⁄ -inch steps up to 3⁄ inch, in 1⁄ -inch steps from 3⁄ inch to 1 inch, in 1⁄ -inch steps from 1 inch to 21⁄ inches, and in 1⁄ -inch steps above 21⁄ inches.
16
8
8
8
4
2
2
2
Tolerance on length is ±0.010 inch.
c These hole sizes have been commonly used for press fitting Standard Series machine dowel pins into materials such as mild steels and cast iron. In soft materials such
as aluminum or zinc die castings, hole size limits are usually decreased by 0.0005 inch to increase the press fit.
d Nonpreferred sizes, not recommended for use in new designs.
DOWEL PINS
Nominal Sizea
or Nominal Pin
Diameter
1⁄
0.0625
16
5⁄ d
0.0781
64
DOWEL PINS
1671
If a dowel pin is driven into a blind hole where no provision is made for releasing air, the
worker assembling the pin may be endangered, and damage may be caused to the associated component, or stresses may be set up. The appendix of the Standard describes one
method of overcoming this problem by providing a small flat surface along the length of a
pin to permit the release of air.
For purposes of marking, the Standard states that each package or lot of dowel pins shall
bear the manufacturer's name or trademark, the BS number, and the grade of pin.
American National Standard Hardened Ground Machine Dowel Pins.—H a r d e n e d
ground machine dowel pins are furnished in two diameter series: Standard Series having
basic diameters 0.0002 inch over the nominal diameter, intended for initial installations;
and Oversize Series having basic diameters 0.001 inch over the nominal diameter,
intended for replacement use.
Preferred Lengths and Sizes: The preferred lengths and sizes in which these pins are normally available are given in Table 1. Other sizes and lengths are produced as required by
the purchaser.
Effective Length: The effective length, Le, must not be less than 75 per cent of the overall
length of the pin.
Shear Strength: Single shear strength values are listed in Table 1. Prior versions of
ANSI/ASME B18.8.2-1995 had listed double shear load minimum values and had specified a minimum single shear strength of 130,000 psi. See ANSI/ASME B18.8.2-1995,
Appendix B for a description of the double shear test.
Designation: These pins are designated by the following data in the sequence shown:
Product name (noun first), including pin series, nominal pin diameter (fraction or decimal
equivalent), length (fraction or decimal equivalent), material, and protective finish, if
required.
Examples: Pins, Hardened Ground Machine Dowel — Standard Series, 3⁄8 × 11⁄2, Steel,
Phosphate Coated.
Pins, Hardened Ground Machine Dowel — Oversize Series, 0.625 × 2.500,
Steel
Installation Precaution: Pins should not be installed by striking or hammering and when
installing with a press, a shield should be used and safety glasses worn.
American National Standard Hardened Ground Production Dowel Pins.—H a r d ened ground production dowel pins have basic diameters that are 0.0002 inch over the
nominal pin diameter.
Preferred Lengths and Sizes: The preferred lengths and sizes in which these pins are
available are given in Table 2. Other sizes and lengths are produced as required by the purchaser.
Shear Strength: Single shear strength values are listed in Table 2. Prior versions of
ANSI/ASME B18.8.2-1995 had listed double shear load minimum values and had specified a minimum single shear strength of 102,000 psi. See ANSI/ASME B18.8.2-1995,
Appendix B for a description of the double shear test.
Ductility: These standard pins are sufficiently ductile to withstand being pressed into
holes 0.0005 inch smaller than the nominal pin diameter in hardened steel without cracking or shattering.
Designation: These pins are designated by the following data in the sequence shown:
Product name (noun first), nominal pin diameter (fraction or decimal equivalent), length
(fraction or decimal equivalent), material, and protective finish, if required.
Examples: Pins, Hardened Ground Production Dowel, 1⁄8 × 3⁄4, Steel, Phosphate Coated
Pins, Hardened Ground Production Dowel, 0.375 × 1.500, Steel
1672
DOWEL PINS
Table 2. American National Standard Hardened Ground Production Dowel Pins
Nominal
Sizea or
Nominal
Pin Diameter
Corner Radius,
R
Suggested Hole
Diameterc
Basic
Max
Min
Max
Min
Range of
Preferred
Lengths,b L
Max
Min
1⁄
16
0.0625
0.0627
0.0628
0.0626
0.020
0.010
3⁄ –
16 1
395
0.0625
0.0620
3⁄
32
0.0938
0.0939
0.0940
0.0938
0.020
0.010
3⁄ –2
16
700
0.0937
0.0932
7⁄
64
0.1094
0.1095
0.1096
0.1094
0.020
0.010
3⁄ –2
16
950
0.1094
0.1089
1⁄
8
0.1250
0.1252
0.1253
0.1251
0.020
0.010
3⁄ –2
16
1,300
0.1250
0.1245
5⁄
32
0.1562
0.1564
0.1565
0.1563
0.020
0.010
3⁄ –2
16
2,050
0.1562
0.1557
3⁄
16
0.1875
0.1877
0.1878
0.1876
0.020
0.010
3⁄ –2
16
2,950
0.1875
0.1870
7⁄
32
0.2188
0.2189
0.2190
0.2188
0.020
0.010
1⁄ –2
4
3,800
0.2188
0.2183
1⁄
4
0.2500
0.2502
0.2503
0.2501
0.020
0.010
1⁄ –11⁄ ,
4
2
13⁄4, 2–21⁄2
5,000
0.2500
0.2495
5⁄
16
0.3125
0.3127
0.3128
0.3126
0.020
0.010
5⁄ –11⁄ ,
16
2
13⁄4, 2–21⁄2
8,000
0.3125
0.3120
3⁄
8
0.3750
0.3752
0.3753
0.3751
0.020
0.010
3⁄ –11⁄ ,
8
2
13⁄4, 2–3
11,500
0.3750
0.3745
Pin Diameter, A
Single Shear
Load,
Calculated,lb
a Where specifying nominal pin size in decimals, zeros preceding decimal and in the fourth decimal
place are omitted.
b Lengths increase in 1⁄ -inch steps up to 1 inch, in 1⁄ -inch steps from 1 inch to 2 inches and then are
16
8
21⁄4, 21⁄2, and 3 inches.
c These hole sizes have been commonly used for press fitting production dowel pins into materials
such as mild steels and cast iron. In soft materials such as aluminum or zinc die castings, hole size limits are usually decreased by 0.0005 inch to increase the press fit.
American National Standard Unhardened Ground Dowel Pins.—U n h a r d e n e d
ground dowel pins are normally produced by grinding the outside diameter of commercial
wire or rod material to size. Consequently, the maximum diameters of the pins, as specified
in Table 3, are below the minimum commercial stock sizes by graduated amounts from
0.0005 inch on the 1⁄16-inch nominal pin size to 0.0028 inch on the 1-inch nominal pin size.
Preferred Lengths and Sizes: The preferred lengths and sizes in which unhardened
ground pins are normally available are given in Table 3. Other sizes and lengths are produced as required by the purchaser.
Shear Strength: These pins must have a single shear strength of 64,000 psi minimum for
pins made from steel and 40,000 psi minimum for pins made from brass and must be capable of withstanding the minimum double shear loads given in Table 3 when tested in accordance with the procedure outlined in ANSI/ASME B18.8.2-1995, Appendix B.
Designation: These pins are designated by the following data in the order shown: Product name (noun first), nominal pin diameter (fraction or decimal equivalent), length (fraction or decimal equivalent), material, and protective finish, if required.
Examples: Pins, Unhardened Ground Dowel, 1⁄8 × 3⁄4, Steel
Pins, Unhardened Ground Dowel, 0.250 × 2.500, Steel, Zinc Plated
DOWEL PINS
1673
Table 3. American National Standard Unhardened Ground Dowel Pins
Nominal Sizea
or Basic Pin
Diameter
1
Pin
Diameter, A
Chamfer
Length,C
Range of
Preferred
Lengths,b
L
Suggested
Hole Diameterc
Double Shear Load
Min, lb.
CarbonSteel
Brass
0.0580
350
220
0.0907
0.0892
820
510
0.1062
0.1047
1,130
710
1⁄ –2
4
0.1217
0.1202
1,490
930
0.005
1⁄ –2
4
0.1528
0.1513
2,350
1,470
0.025
0.005
1⁄ –2
4
0.1840
0.1825
3,410
2,130
0.025
0.005
1⁄ –2
4
0.2151
0.2136
4,660
2,910
0.2465
0.025
0.005
1⁄ –11⁄ ,
4
2
0.2462
0.2447
6,120
3,810
0.3094
0.3089
0.040
0.020
5⁄ –11⁄ ,
16
2
13⁄4, 2–21⁄2
0.3085
0.3070
9,590
5,990
0.3750
0.3717
0.3712
0.040
0.020
3⁄ –11⁄ ,
8
2
13⁄4, 2–21⁄2
0.3708
0.3693
13,850
8,650
7⁄
16
0.4375
0.4341
0.4336
0.040
0.020
7⁄ –5⁄ , 3⁄ , 7⁄ –11⁄ ,
16 8 4 8
2
13⁄4, 2–21⁄2
0.4331
0.4316
18,900
11,810
1⁄
2
0.5000
0.4964
0.4959
0.040
0.020
1⁄ , 5⁄ , 3⁄ , 7⁄ ,
2 8 4 8
13⁄4, 2–3
0.4954
0.4939
24,720
15,450
5⁄
8
0.6250
0.6211
0.6206
0.055
0.035
5⁄ , 3⁄ , 7⁄ , 1–11⁄ , 13⁄ ,
8 4 8
2
4
2, 21⁄2–4
0.6200
0.6185
38,710
24,190
3⁄
4
0.7500
0.7458
0.7453
0.055
0.035
3⁄ , 7⁄ , 1, 11⁄ , 11⁄ ,
4 8
4
2
13⁄4, 2, 21⁄2–4
0.7446
0.7431
55,840
34,900
7⁄
8
0.8750
0.8705
0.8700
0.070
0.050
7⁄ , 1, 11⁄ , 11⁄ , 13⁄ ,
8
4
2
4
2, 21⁄2–4
0.8692
0.8677
76,090
47,550
1.0000
0.9952
0.9947
0.070
0.050
1, 11⁄4, 11⁄2, 13⁄4, 2,
21⁄2–4
0.9938
0.9923
99,460
62,160
Max
Min
Max
Max
Min
0.005
1⁄ –1
4
0.0595
0.025
0.005
1⁄ –11⁄
4
2
0.1063
0.025
0.005
0.1223
0.1218
0.025
0.005
0.1562
0.1535
0.1530
0.025
3⁄
16
0.1875
0.1847
0.1842
7⁄
32
0.2188
0.2159
0.2154
1⁄
4
0.2500
0.2470
5⁄
16
0.3125
3⁄
8
1⁄
16
0.0625
0.0600
0.0595
0.025
3⁄
32
0.0938
0.0912
0.0907
d7⁄
64
0.1094
0.1068
1⁄
8
0.1250
5⁄
32
Min
…
13⁄4, 2–21⁄2
1–11⁄2,
a Where specifying pin size in decimals, zeros preceding decimal and in the fourth decimal place are
omitted.
b Lengths increase in 1⁄ -inch increments from 1⁄ to 1 inch, in 1⁄ -inch increments from 1 inch to 2
16
4
8
inches, and in 1⁄4-inch increments from 2 to 21⁄2 inches, and in 1⁄2-inch increments from 21⁄2 to 4 inches.
c These hole sizes have been found to be satisfactory for press fitting pins into mild steel and cast and
malleable irons. In soft materials such as aluminum alloys or zinc die castings, hole size limits are usually decreased by 0.0005 inch to increase the press fit.
d Nonpreferred size, not recommended for use in new designs.
American National Standard Straight Pins.—The diameter of both chamfered and
square end straight pins is that of the commercial wire or rod from which the pins are made.
The tolerances shown in Table 4 are applicable to carbon steel and some deviations in the
diameter limits may be necessary for pins made from other materials.
1674
STRAIGHT PINS
Table 4. American National Standard Chamfered and Square End Straight Pins
CHAMFERED STRAIGHT PIN
Nominal
Sizea or Basic
Pin Diameter
1⁄
16
3⁄
32
7⁄
64
1⁄
8
5⁄
32
3⁄
16
7⁄
32
1⁄
4
Pin Diameter, A
SQUARE END STRAIGHT PIN
Chamfer Length, C
Max
Min
Max
Min
0.062
0.094
0.109
0.125
0.156
0.0625
0.0937
0.1094
0.1250
0.1562
0.0605
0.0917
0.1074
0.1230
0.1542
0.025
0.025
0.025
0.025
0.025
0.005
0.00
0.005
0.005
0.005
0.188
0.219
0.250
0.1875
0.2187
0.2500
0.1855
0.2167
0.2480
0.025
0.025
0.025
0.005
0.005
0.005
Nominal
Sizeb or Basic
Pin Diameter
5⁄
16
3⁄
8
7⁄
16
1⁄
2
5⁄
8
3⁄
4
7⁄
8
1
Pin Diameter, A
Chamfer Length, C
Max
Min
Max
Min
0.312
0.375
0.438
0.500
0.625
0.3125
0.3750
0.4375
0.5000
0.6250
0.3105
0.3730
0.4355
0.4980
0.6230
0.040
0.040
0.040
0.040
0.055
0.020
0.020
0.020
0.020
0.035
0.750
0.875
1.000
0.7500
0.8750
1.0000
0.7480
0.8730
0.9980
0.055
0.055
0.055
0.035
0.035
0.035
a Where specifying nominal size in decimals, zeros preceding decimal point are omitted.
b Where specifying nominal size in decimals, zeros preceding decimal point are omitted.
Length Increments: Lengths are as specified by the purchaser; however, it is recommended that nominal pin lengths be limited to increments of not less than 0.062 inch.
Material: Straight pins are normally made from cold drawn steel wire or rod having a
maximum carbon content of 0.28 per cent. Where required, pins may also be made from
corrosion resistant steel, brass, or other metals.
Designation: Straight pins are designated by the following data, in the sequence shown:
Product name (noun first), nominal size (fraction or decimal equivalent), material, and
protective finish, if required.
Examples: Pin, Chamfered Straight, 1⁄8 × 1.500, Steel
Pin, Square End Straight, 0.250 × 2.250, Steel, Zinc Plated
American National Standard Taper Pins.—Taper pins have a uniform taper over the
pin length with both ends crowned. Most sizes are supplied in commercial and precision
classes, the latter having generally tighter tolerances and being more closely controlled in
manufacture.
Diameters: The major diameter of both commercial and precision classes of pins is the
diameter of the large end and is the basis for pin size. The diameter at the small end is computed by multiplying the nominal length of the pin by the factor 0.02083 and subtracting
the result from the basic pin diameter. See also Table 5.
Taper: The taper on commercial class pins is 0.250 ± 0.006 inch per foot and on the precision class pins is 0.250 ± 0.004 inch per foot of length.
Materials: Unless otherwise specified, taper pins are made from SAE 1211 steel or cold
drawn SAE 1212 or 1213 steel or equivalents, and no mechanical property requirements
apply.
Hole Sizes: Under most circumstances, holes for taper pins require taper reaming. Sizes
and lengths of taper pins for which standard reamers are available are given in Table 6.
Drilling specifications for taper pins are given below.
TAPER PINS
1675
Designation: Taper pins are designated by the following data in the sequence shown:
Product name (noun first), class, size number (or decimal equivalent), length (fraction or
three-place decimal equivalent), material, and protective finish, if required.
Examples: Pin, Taper (Commercial Class) No. 0 × 3⁄4, Steel
Pin, Taper (Precision Class) 0.219 × 1.750, Steel, Zinc Plated
Table 5. Nominal Diameter at Small Ends of Standard Taper Pins
Pin
Length in
inches
0
1
2
3
4
5
6
7
8
9
10
3⁄
4
0.140
0.156
0.177
0.203
0.235
0.273
0.325
0.393
0.476
0.575
0.690
11⁄4
0.135
0.130
0.151
0.146
0.172
0.167
0.198
0.192
0.230
0.224
0.268
0.263
0.320
0.315
0.388
0.382
0.471
0.466
0.570
0.565
0.685
0.680
11⁄2
0.125
0.141
0.162
0.187
0.219
0.258
0.310
0.377
0.460
0.560
0.675
13⁄4
0.120
0.136
0.157
0.182
0.214
0.252
0.305
0.372
0.455
0.554
0.669
2
21⁄4
0.114
0.109
0.130
0.125
0.151
0.146
0.177
0.172
0.209
0.204
0.247
0.242
0.299
0.294
0.367
0.362
0.450
0.445
0.549
0.544
0.664
0.659
21⁄2
0.104
0.120
0.141
0.166
0.198
0.237
0.289
0.356
0.440
0.539
0.654
23⁄4
0.099
0.115
0.136
0.161
0.193
0.232
0.284
0.351
0.434
0.534
0.649
3
31⁄4
0.094
…
0.110
…
0.131
…
0.156
0.151
0.188
0.182
0.227
0.221
0.279
0.273
0.346
0.340
0.429
0.424
0.528
0.523
0.643
0.638
31⁄2
…
…
…
0.146
0.177
0.216
0.268
0.335
0.419
0.518
0.633
33⁄4
…
…
…
0.141
0.172
0.211
0.263
0.330
0.414
0.513
0.628
4
41⁄4
…
…
…
…
…
…
0.136
0.131
0.167
0.162
0.206
0.201
0.258
0.253
0.326
0.321
0.409
0.403
0.508
0.502
0.623
0.617
41⁄2
…
…
…
0.125
0.156
0.195
0.247
0.315
0.398
0.497
0.612
5
51⁄2
…
…
…
…
…
…
…
…
0.146
…
0.185
…
0.237
…
0.305
0.294
0.389
0.377
0.487
0.476
0.602
0.591
6
…
…
…
…
…
…
…
0.284
0.367
0.466
0.581
1
Pin Number and Small End Diameter for Given Length
Drilling Specifications for Taper Pins.—When helically fluted taper pin reamers are
used, the diameter of the through hole drilled prior to reaming is equal to the diameter at the
small end of the taper pin. (See Table 5.) However, when straight fluted taper reamers are
to be used, it may be necessary, for long pins, to step drill the hole before reaming, the number and sizes of the drills to be used depending on the depth of the hole (pin length).
To determine the number and sizes of step drills required: Find the length of pin to be
used at the top of the chart on page 1676 and follow this length down to the intersection
with that heavy line which represents the size of taper pin (see taper pin numbers at the
right-hand end of each heavy line). If the length of pin falls between the first and second
dots, counting from the left, only one drill is required. Its size is indicated by following the
nearest horizontal line from the point of intersection (of the pin length) on the heavy line
over to the drill diameter values at the left. If the intersection of pin length comes between
the second and third dots, then two drills are required. The size of the smaller drill then corresponds to the intersection of the pin length and the heavy line and the larger is the corresponding drill diameter for the intersection of one-half this length with the heavy line.
Should the pin length fall between the third and fourth dots, three drills are required. The
smallest drill will have a diameter corresponding to the intersection of the total pin length
with the heavy line, the next in size will have a diameter corresponding to the intersection
of two-thirds of this length with the heavy line and the largest will have a diameter corresponding to the intersection of one-third of this length with the heavy line. Where the intersection falls between two drill sizes, use the smaller.
1676
TAPER-PIN REAMER DRILLS
Chart to Facilitate Selection of Number and Sizes of Drills
for Step-Drilling Prior to Taper Reaming
Drill
dia
0.0156
0.0312
0.0469
0.0625
0.0781
0.0938
0.1094
0.1250
0.1406
0.1562
0.1719
0.1875
0.2031
0.2188
0.2344
0.2500
0.2656
0.2812
0.2969
0.3125
0.3281
0.3438
0.3594
0.3750
0.3906
0.4062
0.4219
0.4375
0.4531
0.4688
0.4844
0.5000
0.5156
0.5312
0.5469
0.5625
0.5781
0.5938
0.6094
0.6250
0.6406
0.6562
0.6719
0.6875
0.7031
Pin
dia
Length of Pin in Inches
2
3
4
1
5
6
7/0
0.0625
0.0780
0.0940
0.1090
0.1250
0.1410
0.1560
6/0
5/0
4/0
3/0
2/0
0
1
2
3
4
0.1720
0.1930
0.2190
5
6
0.2500
0.2890
7
0.3410
8
0.4090
9
0.4920
10
0.5910
0.7060
TAPER AND GROOVED PINS
1677
Examples:For a No. 10 taper pin 6inches long, three drills would be used,
of the sizes and for the depths shown in
the accompanying diagram.
For a No. 10 taper pin 3-inches long,
two drills would be used because the 3inch length falls between the second
and third dots. The first or through drill
will be 0.6406 inch and the second drill,
0.6719 inch for a depth of 11⁄2 inches.
Table 6. American National Standard Taper Pins ANSI/ASME B18.8.2-1995
Pin Size
Number and
Basic Pin Dia.a
Major Diameter (Large End), A
Commercial Class
Precision Class
Max
Min
Max
Min
End Crown
Radius, R
Max
Min
Range of Lengths,b
L
Stand. Reamer Avail.c
Other
7⁄
0
6⁄
0
5⁄
0
4⁄
0
3⁄
0
2⁄
0
0.0625
0.0638
0.0618
0.0635
0.0625
0.072
0.052
…
0.0780
0.0793
0.0773
0.0790
0.0780
0.088
0.068
…
0.0940
0.0953
0.0933
0.0950
0.0940
0.104
0.084
0.1090
0.1103
0.1083
0.1100
0.1090
0.119
0.099
0.1250
0.1263
0.1243
0.1260
0.1250
0.135
0.115
0.1410
0.1423
0.1403
0.1420
0.1410
0.151
0.131
0
0.1560
0.1573
0.1553
0.1570
0.1560
0.166
0.146
1
0.1720
0.1733
0.1713
0.1730
0.1720
0.182
0.162
2
0.1930
0.1943
0.1923
0.1940
0.1930
0.203
0.183
3
0.2190
0.2203
0.2183
0.2200
0.2190
0.229
0.209
4
0.2500
0.2513
0.2493
0.2510
0.2500
0.260
0.240
5
0.2890
0.2903
0.2883
0.2900
0.2890
0.299
0.279
6
0.3410
0.3423
0.3403
0.3420
0.3410
0.351
0.331
7
0.4090
0.4103
0.4083
0.4100
0.4090
0.419
0.399
8
0.4920
0.4933
0.4913
0.4930
0.4920
0.502
0.482
9
0.5910
0.5923
0.5903
0.5920
0.5910
0.601
0.581
10
0.7060
0.7073
0.7053
0.7070
0.7060
0.716
0.696
11
12
13
14
0.8600
1.0320
1.2410
1.5210
0.8613
1.0333
1.2423
1.5223
0.8593
1.0313
1.2403
1.5203
…
…
…
…
…
…
…
…
0.870
1.042
1.251
1.531
0.850
1.022
1.231
1.511
1⁄ –1
4
1⁄ –1
4
1⁄ –1
4
1⁄ –11⁄
2
4
1⁄ –11⁄
2
4
3⁄ –11⁄
4
4
3⁄ –11⁄
4
2
3⁄ –13⁄
4
4
3⁄ –2
4
1
1–2 ⁄2
11⁄4–3
11⁄4–33⁄4
11⁄4–41⁄2
11⁄4–51⁄4
11⁄2–6
…
…
…
…
1⁄ –1
4
1⁄ –1⁄
4 2
11⁄4, 11⁄2
11⁄4–2
11⁄4–2
11⁄2–21⁄2
11⁄2–3
11⁄2–3
13⁄4–3
2–4
21⁄4–4
23⁄4–6
31⁄4–6
4–8
43⁄4–8
51⁄2–8
61⁄4–8
2–8
2–9
3–11
3–13
a When specifying nominal pin size in decimals, zeros preceding the decimal and in the fourth decimal place are omitted.
b Lengths increase in 1⁄ -inch steps up to 1 inch and in 1⁄ -inch steps above 1 inch.
8
4
c Standard reamers are available for pin lengths in this column.
For nominal diameters, B, see Table 5.
American National Standard Grooved Pins.—These pins have three equally spaced
longitudinal grooves and an expanded diameter over the crests of the ridges formed by the
material displaced when the grooves are produced. The grooves are aligned with the axes
of the pins. There are seven types of grooved pins as shown in the illustration on
page 1679.
Standard Sizes and Lengths: The standard sizes and lengths in which grooved pins are
normally available are given in Table 7.
1678
PINS AND STUDS
Materials: Grooved pins are normally made from cold drawn low carbon steel wire or
rod. Where additional performance is required, carbon steel pins may be supplied surface
hardened and heat treated to a hardness consistent with the performance requirements.
Pins may also be made from alloy steel, corrosion resistant steel, brass, Monel and other
non-ferrous metals having chemical properties as agreed upon between manufacturer and
purchaser.
Performance Requirements: Grooved pins are required to withstand the minimum double shear loads given in Table 7 for the respective materials shown, when tested in accordance with the Double Shear Testing of Pins as set forth in ANSI/ASME B18.8.2-1995,
Appendix B.
Hole Sizes: To obtain maximum product retention under average conditions, it is recommended that holes for the installation of grooved pins be held as close as possible to the
limits shown in Table 7. The minimum limits correspond to the drill size, which is the same
as the basic pin diameter. The maximum limits are generally suitable for length-diameter
ratios of not less than 4 to 1 nor greater than 10 to 1. For smaller length-to-diameter ratios,
the hole should be held closer to the minimum limits where retention is critical. Conversely
for larger ratios where retention requirements are less important, it may be desirable to
increase the hole diameters beyond the maximum limits shown.
Designation: Grooved pins are designated by the following data in the sequence shown:
Product name (noun first) including type designation, nominal size (number, fraction or
decimal equivalent), length (fraction or decimal equivalent), material, including specification or heat treatment where necessary, protective finish, if required.
Examples: Pin, Type A Grooved, 3⁄32 × 3⁄4, Steel, Zinc Plated
Pin, Type F Grooved, 0.250 × 1.500, Corrosion Resistant Steel
American National Standard Grooved T-Head Cotter Pins and Round Head
Grooved Drive Studs.—The cotter pins have a T-head and the studs a round head. Both
pins and studs have three equally spaced longitudinal grooves and an expanded diameter
over the crests of the raised ridges formed by the material displaced when the grooves are
formed.
Standard Sizes and Lengths: The standard sizes and range of standard lengths are given
in Tables 8 and 9.
Material: Unless otherwise specified these pins are made from low carbon steel. Where
so indicated by the purchaser they may be made from corrosion resistant steel, brass or
other non-ferrous alloys.
Hole Sizes: To obtain optimum product retention under average conditions, it is recommended that holes for the installation of grooved T-head cotter pins and grooved drive
studs be held as close as possible to the limits tabulated. The minimum limits given correspond to the drill size, which is equivalent to the basic shank diameter. The maximum limits shown are generally suitable for length-diameter ratios of not less than 4 to 1 and not
greater than 10 to 1. For smaller length-to-diameter ratios, the holes should be held closer
to minimum limits where retention is critical. Conversely, for larger length-to-diameter
ratios or where retention requirements are not essential, it may be desirable to increase the
hole diameter beyond the maximum limits shown.
Designation: Grooved T-head cotter pins and round head grooved drive studs are designated by the following data, in the order shown: Product name (noun first), nominal size
(number, fraction or decimal equivalent), length (fraction or decimal equivalent), material
including specification or heat treatment where necessary, and protective finish, if
required.
Examples: Pin, Grooved T-Head Cotter, 1⁄4 × 11⁄4, Steel, Zinc Plated
Drive Stud, Round Head Grooved, No. 10 × 1⁄2, Corrosion Resistant Steel
L
L
See Note 3
B
E
A
F See Note 2
Type A
B
See Note 3
D
D
C
C
C
A
A
F See Note 2
Type C
E
L
2
E
B
L
E
L
30° – 45° Both Ends
Type F
E E
L
2
L
4
L
2
L
E
PINS
A
F See Note 2
Type B
A
F
See Note 2
Type D
E
See Note 3
J
A
F
See Note 2
Type E
F
E
L
H
B
F
L
2
C
K
A
G
Type G
F Both Ends – See Note 2
1679
Types of American National Standard Grooved Pins, ANSI/ASME B18.8.2-1995 (For notes see bottom of Table 7.)
Chamfer
Pilot
Length, C Length,b D
Ref
Min
0.015
…
0.031
…
0.031
0.016
0.031
0.016
0.031
0.016
0.031
0.016
0.031
0.016
0.062
0.031
0.062
0.031
0.062
0.031
0.062
0.031
0.094
0.047
0.094
0.047
0.094
0.047
0.094
0.047
Crown
Height,b E
Max
Min
…
…
…
…
0.0115
0.0015
0.0137
0.0037
0.0141
0.0041
0.0160
0.0060
0.0180
0.0080
0.0220
0.0120
0.0230
0.0130
0.0270
0.0170
0.0310
0.0210
0.0390
0.0290
0.0440
0.0340
0.0520
0.0420
0.0570
0.0470
Crown
Radius,b F
Max
Min
…
…
…
…
0.088
0.068
0.104
0.084
0.135
0.115
0.150
0.130
0.166
0.146
0.198
0.178
0.260
0.240
0.291
0.271
0.322
0.302
0.385
0.365
0.479
0.459
0.541
0.521
0.635
0.615
Neck
Width, G
Max
Min
…
…
…
…
…
…
…
…
0.038
0.028
0.038
0.028
0.069
0.059
0.069
0.059
0.069
0.059
0.101
0.091
0.101
0.091
0.132
0.122
0.132
0.122
0.195
0.185
0.195
0.185
Shoulder
Length, H
Max
Min
…
…
…
…
…
…
…
…
0.041
0.031
0.041
0.031
0.041
0.031
0.057
0.047
0.057
0.047
0.072
0.062
0.072
0.062
0.104
0.094
0.135
0.125
0.135
0.125
0.135
0.125
Neck
Radius, J
Ref
…
…
…
…
0.016
0.016
0.031
0.031
0.031
0.047
0.047
0.062
0.062
0.094
0.094
Neck
Diameter, K
Max
Min
…
…
…
…
…
…
…
…
0.067
0.057
0.082
0.072
0.088
0.078
0.109
0.099
0.130
0.120
0.151
0.141
0.172
0.162
0.214
0.204
0.255
0.245
0.298
0.288
0.317
0.307
Range of
Standard
Lengthsc
1⁄ –1⁄
8 2
1⁄ –5⁄
8 8
1⁄ –1
8
1⁄ –1
4
1⁄ –11⁄
4
4
1⁄ –11⁄
4
4
1⁄ –11⁄
4
2
3⁄ –2
8
3⁄ –21⁄
8
4
1⁄ –3
2
1⁄ –31⁄
2
4
5⁄ –31⁄
8
2
3⁄ –41⁄
4
4
7⁄ –41⁄
8
2
1–41⁄2
a For expanded diameters, B, see ANSI/ASME B18.8.2-1995.
b Pins in 1⁄ - and 3⁄ -inch sizes of any length and all sizes of 1⁄ -inch nominal length or shorter are not crowned or chamfered.
32
64
4
c Standard lengths increase in 1⁄ -inch steps from 1⁄ to 1 inch, and in 1⁄ -inch steps above 1 inch. Standard lengths for the 1⁄ -, 3⁄ -, 1⁄ -,
8
8
4
32
64
16
3
7
1
length for the ⁄32-, ⁄64-, and ⁄8-inch sizes do not apply to Type G grooved pins.
d Non-stock items, not recommended for new designs.
and 5⁄64-inch sizes and the 1⁄4-inch
Nominal Pin Size
Pin Material
1⁄
32
3⁄
64
Steels
1⁄
16
5⁄
64
3⁄
32
7⁄
64
1⁄
8
5⁄
32
3⁄
16
7⁄
32
1⁄
4
5⁄
16
3⁄
8
7⁄
16
1⁄
2
15,000
35,200
24,800
12,100
19,600
46,000
32,400
15,800
0.4428
0.4375
0.5060
0.5000
Double Shear Load, Min, lb
Low Carbon
Alloy (Rc 40 – 48 hardness)
Corrosion Resistant
Brass
Maximum Diameter
Minimum Diameter
100
180
140
60
220
400
300
140
0.0324
0.0312
0.0482
0.0469
410
620
890
1,220
1,600
2,300
3,310
4,510
5,880
7,660
11,000
720
1,120
1,600
2,180
2,820
4,520
6,440
8,770
11,500
17,900
26,000
540
860
1,240
1,680
2,200
3,310
4,760
6,480
8,460
12,700
18,200
250
390
560
760
990
1,540
2,220
3,020
3,950
6,170
9,050
Recommended Hole Sizes for Unplated Pins (The minimum drill size is the same as the pin size. See also text on page 1678.)
0.0640
0.0798
0.0956
0.1113
0.1271
0.1587
0.1903
0.2219
0.2534
0.3166
0.3797
0.0625
0.0781
0.0938
0.1094
0.1250
0.1563
0.1875
0.2188
0.2500
0.3125
0.3750
PINS AND STUDS
Pin
Diameter,a A
Max
Min
0.0312
0.0302
0.0469
0.0459
0.0625
0.0615
0.0781
0.0771
0.0938
0.0928
0.1094
0.1074
0.1250
0.1230
0.1563
0.1543
0.1875
0.1855
0.2188
0.2168
0.2500
0.2480
0.3125
0.3105
0.3750
0.3730
0.4375
0.4355
0.5000
0.4980
1680
Table 7. American National Standard Grooved Pins ANSI/ASME B18.8.2-1995
Nominal Size or
Basic Pin
Diameter
1⁄ d
0.0312
32
3⁄ d
0.0469
64
1⁄
0.0625
16
5⁄ d
0.0781
64
3⁄
0.0938
32
7⁄ d
0.1094
64
1⁄
0.1250
8
5⁄
0.1563
32
3⁄
0.1875
16
7⁄
0.2188
32
1⁄
0.2500
4
5⁄
0.3125
16
3⁄
0.3750
8
7⁄
0.4375
16
1⁄
0.5000
2
PINS AND STUDS
1681
Table 8. American National Standard Grooved T-Head Cotter Pins
Nominal
Sizea
or Basic
Shank Dia.
5⁄
0.156
32
3⁄
0.187
16
1⁄
0.250
4
5⁄
0.312
16
23⁄
0.359
64
1⁄
0.500
2
Shank
Diameter, A
Max
0.154
0.186
0.248
0.310
0.358
0.498
Length,
N
Min
0.150
0.182
0.244
0.305
0.353
0.493
Max
0.08
0.09
0.12
0.16
0.18
0.25
Head Dia.,
O
Max
0.26
0.30
0.40
0.51
0.57
0.79
Min
0.24
0.28
0.38
0.48
0.54
0.76
Head Height,
P
Head Width,
Q
Max
0.11
0.13
0.17
0.21
0.24
0.32
Max
0.18
0.22
0.28
0.34
0.38
0.54
Min
0.09
0.11
0.15
0.19
0.22
0.30
Min
0.15
0.18
0.24
0.30
0.35
0.49
Range of
Standard
Lengths,b
L
3⁄ –11⁄
4
8
3⁄ –11⁄
4
4
1–11⁄2
1
1 ⁄8–2
11⁄4–2
2–3
Recommended
Hole Size
Max
0.161
0.193
0.257
0.319
0.366
0.508
Min
0.156
0.187
0.250
0.312
0.359
0.500
a When specifying nominal size in decimals, zeros preceding decimal point and in the fourth decimal
place are omitted.
b Lengths increase in 1⁄ -inch steps from 3⁄ to 11⁄ inch and in 1⁄ -inch steps above 11⁄ inches. For groove
8
4
4
4
4
length, M, dimensions see ANSI/ASME B18.8.2-1995.
For expanded diameter, B, dimensions, see ANSI/ASME B18.8.2-1995.
Table 9. American National Standard Round Head Grooved Drive Studs
Stud Size
Number
and Basic Shank
Diametera
0
0.067
2
0.086
4
0.104
6
0.120
7
0.136
8
0.144
10
0.161
12
0.196
14
0.221
16
0.250
Shank Diameter, A Head Diameter, O
Max
0.067
0.086
0.104
0.120
0.136
0.144
0.161
0.196
0.221
0.250
Min
0.065
0.084
0.102
0.118
0.134
0.142
0.159
0.194
0.219
0.248
Max
0.130
0.162
0.211
0.260
0.309
0.309
0.359
0.408
0.457
0.472
Min
0.120
0.146
0.193
0.240
0.287
0.287
0.334
0.382
0.429
0.443
Head
Height, P
Max
0.050
0.070
0.086
0.103
0.119
0.119
0.136
0.152
0.169
0.174
Min
0.040
0.059
0.075
0.091
0.107
0.107
0.124
0.140
0.156
0.161
Range of
Standard
Lengths,b
L
1⁄ –1⁄
8 4
1⁄ –1⁄
8 4
3⁄ –5⁄
16 16
1⁄ –3⁄
4 8
5⁄ –1⁄
16 2
3⁄ –5⁄
8 8
3⁄ –5⁄
8 8
1⁄ 3⁄
24
1⁄ –3⁄
2 4
1⁄
2
Recommended
Hole Size
Max
0.0686
0.0877
0.1059
0.1220
0.1382
0.1463
0.1636
0.1990
0.2240
0.2534
Min
0.0670
0.0860
0.1040
0.1200
0.1360
0.1440
0.1610
0.1960
0.2210
0.2500
a Where
Drill
Size
51
44
37
31
29
27
20
9
2
1⁄
4
specifying nominal size in decimals, zeros preceding decimal point and in the fourth decimal place are omitted.
b Lengths increase in 1⁄ -inch steps from 1⁄ to 3⁄ inch and in 1⁄ -inch steps above 3⁄ inch.
16
8
8
8
8
For pilot length, M, and expanded diameter, B, dimensions see ANSI/ASME B18.8.2-1995.
1682
PINS
Table 10. American National Standard Slotted Type Spring Pins
Nominal
Sizea
or Basic
Pin
Diameter
Average
Pin
Diameter,
A
Max
Min
Cham
fer
Dia.,
B
Max
Chamfer
Length,
C
Max
Min
Material
Stock
SAE
Thick Recommended SAE 1070 – 30302
Berylness,
Hole
and
lium
1095 and
F
Size
SAE 51420 30304 Copper
Basic Max
Min
Range
of
Practical
Lengthsb
1⁄
16
0.062
0.069
0.066
0.059
0.028
0.007
0.012
0.065
0.062
430
250
270
3⁄ –1
16
5⁄
64
0.078
0.086
0.083
0.075
0.032
0.008
0.018
0.081
0.078
800
460
500
3⁄ –11⁄
16
2
3⁄
32
0.094
0.103
0.099
0.091
0.038
0.008
0.022
0.097
0.094
1,150
670
710
3⁄ –11⁄
16
2
1⁄
8
0.125
0.135
0.131
0.122
0.044
0.008
0.028
0.129
0.125
1,875
1,090
1,170
5⁄ –2
16
9⁄
64
0.141
0.149
0.145
0.137
0.044
0.008
0.028
0.144
0.140
2,175
1,260
1,350
3⁄ –2
8
5⁄
32
0.156
0.167
0.162
0.151
0.048
0.010
0.032
0.160
0.156
2,750
1,600
1,725
7⁄ –21⁄
16
2
3⁄
16
0.188
0.199
0.194
0.182
0.055
0.011
0.040
0.192
0.187
4,150
2,425
2,600
1⁄ –21⁄
2
2
7⁄
32
0.219
0.232
0.226
0.214
0.065
0.011
0.048
0.224
0.219
5,850
3,400
3,650
1⁄ –3
2
1⁄
4
0.250
0.264
0.258
0.245
0.065
0.012
0.048
0.256
0.250
7,050
4,100
4,400
1⁄ –31⁄
2
2
5⁄
16
0.312
0.330
0.321
0.306
0.080
0.014
0.062
0.318
0.312
10,800
6,300
6,750
3⁄ –4
4
3⁄
8
0.375
0.395
0.385
0.368
0.095
0.016
0.077
0.382
0.375
16,300
9,500
10,200
3⁄ , 7⁄ , 1,11⁄ ,
4 8
4
11⁄2,13⁄4, 2–4
7⁄
16
0.438
0.459
0.448
0.430
0.095
0.017
0.077
0.445
0.437
19,800
11,500
12,300
1, 11⁄4,11⁄2,
13⁄4, 2–4
1⁄
2
0.500
0.524
0.513
0.485
0.110
0.025
0.094
0.510
0.500
27,100
15,800
17,000
11⁄4, 11⁄2,
13⁄4, 2–4
5⁄
8
0.625
0.653
0.640
0.608
0.125
0.030
0.125
0.636
0.625
46,000
18,800
…
2–6
3⁄
4
0.750
0.784
0.769
0.730
0.150
0.030
0.150
0.764
0.750
66,000
23,200
…
2–6
a Where specifying nominal size in decimals, zeros preceding decimal point are omitted.
b Length increments are 1⁄ inch from 1⁄ to 1 inch; 1⁄ from 1 inch to 2 inches; and 1⁄ inch from 2 inches
16
8
8
4
to 6 inches.
American National Standard Spring Pins.—These pins are made in two types: one type
has a slot throughout its length; the other is shaped into a coil.
Preferred Lengths and Sizes: The preferred lengths and sizes in which these pins are normally available are given in Tables 10 and 11.
Materials: Spring pins are normally made from SAE 1070–1095 carbon steel, SAE
6150H alloy steel, SAE types 51410 through 51420, 30302 and 30304 corrosion resistant
steels, and beryllium copper alloy, heat treated or cold worked to attain the hardness and
performance characteristics set forth in ANSI/ASME B18.8.2-1995.
Designation: Spring pins are designated by the following data in the sequence shown:
Examples: Pin, Coiled Spring, 1⁄4 × 11⁄4, Standard Duty, Steel, Zinc Plated
Pin, Slotted Spring, 1⁄2 × 3, Steel, Phosphate Coated
Table 11. American National Standard Coiled Type Spring Pins ANSI/ASME B18.8.2-1995
Pin Diameter, A
Heavy
Duty
Max
Min
…
…
…
…
…
…
…
…
0.070
0.066
0.086
0.082
0.103
0.098
0.118
0.113
0.136
0.130
0.168
0.161
0.202
0.194
0.235
0.226
0.268
0.258
0.334
0.322
0.400
0.386
0.466
0.450
0.532
0.514
0.658
0.640
0.784
0.766
Chamfer
Light
Duty
Max
…
…
…
…
0.073
0.089
0.106
0.121
0.139
0.172
0.207
0.240
0.273
0.339
0.405
0.471
0.537
…
…
Min
…
…
…
…
0.067
0.083
0.099
0.114
0.131
0.163
0.196
0.228
0.260
0.324
0.388
0.452
0.516
…
…
Dia.,
B
Max
0.029
0.037
0.045
0.050
0.059
0.075
0.091
0.106
0.121
0.152
0.182
0.214
0.243
0.304
0.366
0.427
0.488
0.613
0.738
Length,
C
Ref
0.024
0.024
0.024
0.024
0.028
0.032
0.038
0.038
0.044
0.048
0.055
0.065
0.065
0.080
0.095
0.095
0.110
0.125
0.150
Recommended
Hole Size
Max
Min
0.032
0.031
0.040
0.039
0.048
0.046
0.053
0.051
0.065
0.061
0.081
0.077
0.097
0.093
0.112
0.108
0.129
0.124
0.160
0.155
0.192
0.185
0.224
0.217
0.256
0.247
0.319
0.308
0.383
0.370
0.446
0.431
0.510
0.493
0.635
0.618
0.760
0.743
1070–1095
and 51420
30302 and
30304
Standard Duty
90a
65
100
135a
145
190a
190
250a
330
265
550
425
775
600
1,050
825
1,400
1,100
2,200
1,700
3,150
2,400
4,200
3,300
5,500
4,300
8,700
6,700
12,600
9,600
17,000
13,300
22,500
17,500
…
35,000b
…
50,000b
SAE Material Number
1070–1095
30302 and
and 51420
30304
Heavy Duty
…
…
…
…
…
…
…
…
475
360
800
575
1,150
825
1,500
1,150
2,000
1,700
3,100
2,400
4,500
3,500
5,900
4,600
7,800
6,200
12,000
9,300
18,000
14,000
23,500
18,000
32,000
25,000
…
48,000b
…
70,000b
1070–1095
and 51420
30302 and
30304
Light Duty
…
…
…
…
…
…
…
…
205
160
325
250
475
360
650
500
825
650
1,300
1,000
1,900
1,450
2,600
2,000
3,300
2,600
5,200
4,000
…
…
…
…
…
…
…
…
…
…
1683
a Sizes 1⁄ inch through 0.052 inch are not available in SAE 1070–1095 carbon steel.
32
b Sizes 5⁄ inch and larger are produced from SAE 6150H alloy steel, not SAE 1070–1095 carbon steel. Practical lengths, L, for sizes 1⁄ through 0.052 inch are 1⁄ through
8
32
8
5⁄ inch and for the 7⁄ -inch size, 1⁄ through 13⁄ inches. For lengths of other sizes see Table 10.
8
64
4
4
PINS
Nominal Size
or Basic Pin
Diameter
1⁄
0.031
32
0.039
3⁄
0.047
64
0.052
1⁄
0.062
16
5⁄
0.078
64
3⁄
0.094
32
7⁄
0.109
64
1⁄
0.125
8
5⁄
0.156
32
3⁄
0.188
16
7⁄
0.219
32
1⁄
0.250
4
5⁄
0.312
16
3⁄
0.375
8
7⁄
0.438
16
1⁄
0.500
2
5⁄
0.625
8
3⁄
0.750
4
Standard
Duty
Max
Min
0.035
0.033
0.044
0.041
0.052
0.049
0.057
0.054
0.072
0.067
0.088
0.083
0.105
0.099
0.120
0.114
0.138
0.131
0.171
0.163
0.205
0.196
0.238
0.228
0.271
0.260
0.337
0.324
0.403
0.388
0.469
0.452
0.535
0.516
0.661
0.642
0.787
0.768
1684
RETAINING RINGS
RETAINING RINGS
Retaining Rings.—The purpose of a retaining ring is to act as an artificial shoulder that
will retain an object in a housing (internal ring), as shown in Fig. 1, or on a shaft (external
ring). Two types of retaining ring are common, the stamped ring and the spiral-wound ring.
The stamped type of retaining ring, or snap ring, is stamped from tempered sheet metal and
has a nonuniform cross-section. The typical spiral-wound retaining ring has a uniform
cross-section and is made up of two or more turns of coiled, spring-tempered steel,
although one-turn spiral-wound rings are common. Spiral-wound retaining rings provide a
continuous gapless shoulder to a housing or shaft. Most stamped rings can only be installed
at or near the end of a shaft or housing. The spiral-wound design generally requires installation from the end of a shaft or housing. Both types, stamped and spiral, are usually
installed into grooves on the shaft or housing.
Housing
Retained
Part
Max. Groove
Chamfer
or Radius
+ Max. Side
Clearance
+ Max. Retained
Part Chamfer
or Radius
= Maximum Total
Radius or
Chamfer
Fig. 1. Typical Retaining Ring Installation Showing Maximum Total Radius or Chamfer (Courtesy
Spirolox Retaining Rings)
In the section that follows, Tables 1 through 6 give dimensions and data on general-purpose tapered and reduced cross-section metric retaining rings (stamped type) covered by
ANSI B27.7-1977, R1993. Tables 1 and 4 cover Type 3AM1 tapered external retaining
rings, Tables 2 and 5 cover Type 3BM1 tapered internal rings, and Tables 3 and 6 cover
Type 3CM1 reduced cross-section external rings. Tables 7 through 10 cover inch sizes of
internal and external spiral retaining rings corresponding to MIL-R-27426 Types A (external) and B (internal), Class 1 (medium duty) and Class 2 (heavy duty). Tables 11 through
17 cover stamped retaining rings in inch sizes.
Table 1. American National Standard Metric Tapered Retaining Rings —
Basic External Series — 3AM1 ANSI B27.7-1977, R1993
RETAINING RINGS
1685
Shaft
Dia.
Table 1. (Continued) American National Standard Metric Tapered Retaining Rings
— Basic External Series — 3AM1 ANSI B27.7-1977, R1993
Ring
Free
Dia.
Groove
Thick
ness
Dia.
Width Depth
d ref
Ring
Edge
Margin
Z min
Shaft
Diam
S
Free
Dia.
D
Groove
Thick
ness
Dia.
Width Depth
W
d ref
Edge
Margin
S
D
t
G
W
t
G
4
3.60
0.25
3.80
0.32
0.1
0.3
36
33.25
1.3
33.85
1.4
1.06
3.2
5
4.55
0.4
4.75
0.5
0.13
0.4
38
35.20
1.3
35.8
1.4
1.10
Z min
3.3
6
5.45
0.4
5.70
0.5
0.15
0.5
40
36.75
1.6
37.7
1.75
1.15
3.4
7
6.35
0.6
6.60
0.7
0.20
0.6
42
38.80
1.6
39.6
1.75
1.20
3.6
8
7.15
0.6
7.50
0.7
0.25
0.8
43
39.65
1.6
40.5
1.75
1.25
3.8
9
8.15
0.6
8.45
0.7
0.28
0.8
45
41.60
1.6
42.4
1.75
1.30
3.9
10
9.00
0.6
9.40
0.7
0.30
0.9
46
42.55
1.6
43.3
1.75
1.35
4.0
11
10.00
0.6
10.35
0.7
0.33
1.0
48
44.40
1.6
45.2
1.75
1.40
4.2
12
10.85
0.6
11.35
0.7
0.33
1.0
50
46.20
1.6
47.2
1.75
1.40
4.2
13
11.90
0.9
12.30
1.0
0.35
1.0
52
48.40
2.0
49.1
2.15
1.45
4.3
14
12.90
0.9
13.25
1.0
0.38
1.2
54
49.9
2.0
51.0
2.15
1.50
4.5
15
13.80
0.9
14.15
1.0
0.43
1.3
55
50.6
2.0
51.8
2.15
1.60
4.8
16
14.70
0.9
15.10
1.0
0.45
1.4
57
52.9
2.0
53.8
2.15
1.60
4.8
17
15.75
0.9
16.10
1.0
0.45
1.4
58
53.6
2.0
54.7
2.15
1.65
4.9
18
16.65
1.1
17.00
1.2
0.50
1.5
60
55.8
2.0
56.7
2.15
1.65
4.9
19
17.60
1.1
17.95
1.2
0.53
1.6
62
57.3
2.0
58.6
2.15
1.70
5.1
20
18.35
1.1
18.85
1.2
0.58
1.7
65
60.4
2.0
61.6
2.15
1.70
5.1
21
19.40
1.1
19.80
1.2
0.60
1.8
68
63.1
2.0
64.5
2.15
1.75
5.3
22
20.30
1.1
20.70
1.2
0.65
1.9
70
64.6
2.4
66.4
2.55
1.80
5.4
23
21.25
1.1
21.65
1.2
0.67
2.0
72
66.6
2.4
68.3
2.55
1.85
5.5
24
22.20
1.1
22.60
1.2
0.70
2.1
75
69.0
2.4
71.2
2.55
1.90
5.7
25
23.10
1.1
23.50
1.2
0.75
2.3
78
72.0
2.4
74.0
2.55
2.00
6.0
26
24.05
1.1
24.50
1.2
0.75
2.3
80
74.2
2.4
75.9
2.55
2.05
6.1
27
24.95
1.3
25.45
1.4
0.78
2.3
82
76.4
2.4
77.8
2.55
2.10
6.3
28
25.80
1.3
26.40
1.4
0.80
2.4
85
78.6
2.4
80.6
2.55
2.20
6.6
30
27.90
1.3
28.35
1.4
0.83
2.5
88
81.4
2.8
83.5
2.95
2.25
6.7
32
29.60
1.3
30.20
1.4
0.90
2.7
90
83.2
2.8
85.4
2.95
2.30
6.9
34
31.40
1.3
32.00
1.4
1.00
3.0
95
88.1
2.8
90.2
2.95
2.40
7.2
35
32.30
1.3
32.90
1.4
1.05
3.1
100
92.5
2.8
95.0
2.95
2.50
7.5
All dimensions are in millimeters. Sizes −4, −5, and −6 are available in beryllium copper only.
These rings are designated by series symbol and shaft diameter, thus: for a 4 mm diameter shaft,
3AM1-4; for a 20 mm diameter shaft, 3AM1-20; etc.
Ring Free Diameter Tolerances: For ring sizes −4 through −6, +0.05, −0.10 mm; for sizes −7
through −12, +0.05, −0.15 mm; for sizes −13 through − 26, +0.15, −0.25 mm; for sizes −27 through
−38, +0.25, −0.40 mm; for sizes −40 through −50, +0.35, −0.50 mm; for sizes −52 through −62,
+0.35, −0.65 mm; and for sizes −65 through −100, +0.50, −0.75 mm.
Groove Diameter Tolerances: For ring sizes −4 through −6, −0.08 mm; for sizes −7 through −10, −
0.10 mm; for sizes −11 through −15, −0.12 mm; for sizes −16 through −26, −0.15 mm; for sizes −27
through − 36, −0.20 mm; for sizes −38 through −55, −0.30 mm; and for sizes −57 through −100, −
0.40 mm.
Groove Diameter F.I.M. (full indicator movement) or maximum allowable deviation of concentricity between groove and shaft: For ring sizes −4 through −6, 0.03 mm; for ring sizes −7 through −
12, 0.05 mm; for sizes −13 through −28, 0.10 mm; for sizes −30 through −55, 0.15 mm; and for sizes
−57 through − 00, 0.20 mm.
Groove Width Tolerances: For ring size −4, +0.05 mm; for sizes −5 and −6, +0.10 mm, for sizes −
7 through −38, +0.15 mm; and for sizes −40 through − 100, +0.20 mm.
Groove Maximum Bottom Radii,R: For ring sizes −4 through −6, none; for sizes −7 through −18,
0.1 mm; for sizes −19 through −30, 0.2 mm; for sizes −32 through −50, 0.3 mm; and for sizes −52
through −100, 0.4 mm. For manufacturing details not shown, including materials, see ANSI B27.71977, R1993.
1686
RETAINING RINGS
Table 2. American National Standard Metric Tapered Retaining Rings — Basic
Internal Series — 3BM1 ANSI B27.7-1977, R1993
Dia.
Width
Depth
Edge
Margin
Shaft Dia.
Free
Dia.
Thickness
Dia.
Width
Depth
Edge
Margin
Groove
Thickness
Ring
Free
Dia.
Groove
Shaft Dia.
Ring
S
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
30
32
34
35
36
37
38
40
42
45
46
47
48
50
52
55
57
58
60
62
63
D
8.80
10.00
11.10
12.20
13.30
14.25
15.45
16.60
17.70
18.90
20.05
21.10
22.25
23.30
24.40
25.45
26.55
27.75
28.85
29.95
31.10
33.40
35.35
37.75
38.75
40.00
41.05
42.15
44.25
46.60
49.95
51.05
52.15
53.30
55.35
57.90
61.10
63.25
64.4
66.8
68.6
69.9
t
0.4
0.6
0.6
0.6
0.6
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
1.1
1.1
1.1
1.1
1.1
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.6
1.6
1.6
1.6
1.6
1.6
1.6
2.0
2.0
2.0
2.0
2.0
2.0
2.0
G
8.40
9.45
10.50
11.60
12.65
13.70
14.80
15.85
16.90
18.00
19.05
20.10
21.15
22.20
23.30
24.35
25.4
26.6
27.7
28.8
29.8
31.9
33.9
36.1
37.2
38.3
39.3
40.4
42.4
44.5
47.6
48.7
49.8
50.9
53.1
55.3
58.4
60.5
61.6
63.8
65.8
66.9
W
0.5
0.7
0.7
0.7
0.7
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.2
1.2
1.2
1.2
1.2
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.75
1.75
1.75
1.75
1.75
1.75
1.75
2.15
2.15
2.15
2.15
2.15
2.15
2.15
d ref
0.2
0.23
0.25
0.3
0.33
0.35
0.40
0.43
0.45
0.50
0.53
0.55
0.57
0.60
0.65
0.67
0.70
0.80
0.85
0.90
0.90
0.95
0.95
1.05
1.10
1.15
1.15
1.20
1.20
1.25
1.30
1.35
1.40
1.45
1.55
1.65
1.70
1.75
1.80
1.90
1.90
1.95
Z min
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.7
1.8
1.9
2.0
2.1
2.4
2.6
2.7
2.7
2.9
2.9
3.2
3.3
3.5
3.5
3.6
3.6
3.7
3.9
4.0
4.2
4.3
4.6
5.0
5.1
5.3
5.4
5.7
5.7
5.9
S
65
68
70
72
75
78
80
82
85
88
90
92
95
98
100
102
105
108
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
200
210
220
230
240
250
…
D
72.2
75.7
77.5
79.6
83.3
86.8
89.1
91.1
94.4
97.9
100.0
102.2
105.6
109.0
110.7
112.4
115.8
119.2
120.8
126.0
132.4
137.1
142.5
148.5
154.1
159.5
164.5
168.8
175.1
180.3
185.6
191.3
196.6
202.7
207.7
217.8
230.3
240.5
251.4
262.3
273.3
…
t
2.4
2.4
2.4
2.4
2.4
2.8
2.8
2.8
2.8
2.8
2.80
2.8
2.8
2.8
2.8
2.8
2.8
2.8
2.8
2.8
2.8
2.8
2.8
3.2
3.2
3.2
3.2
3.2
4.0
4.0
4.0
4.0
4.0
4.8
4.8
4.8
4.8
4.8
4.8
4.8
4.8
…
G
69.0
72.2
74.4
76.5
79.7
82.8
85.0
87.2
90.4
93.6
95.7
97.8
101.0
104.2
106.3
108.4
111.5
114.6
116.7
121.9
127.0
132.1
137.2
142.3
147.4
152.5
157.6
162.7
167.8
172.9
178.0
183.2
188.4
193.6
198.8
209.0
219.4
230.0
240.6
251.0
261.4
…
W
2.55
2.55
2.55
2.55
2.55
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
2.95
3.40
3.40
3.40
3.40
3.40
4.25
4.25
4.25
4.25
4.25
5.10
5.10
5.10
5.10
5.10
5.10
5.10
5.10
…
d ref
2.00
2.10
2.20
2.25
2.35
2.40
2.50
2.60
2.70
2.80
2.85
2.90
3.00
3.10
3.15
3.20
3.25
3.30
3.35
3.45
3.50
3.55
3.60
3.65
3.70
3.75
3.80
3.85
3.90
3.95
4.00
4.10
4.20
4.30
4.40
4.50
4.70
5.00
5.30
5.50
5.70
…
Z min
6.0
6.3
6.6
6.7
7.1
7.2
7.5
7.8
8.1
8.4
8.6
8.7
9.0
9.3
9.5
9.6
9.8
9.9
10.1
10.4
10.5
10.7
10.8
11.0
11.1
11.3
11.4
11.6
11.7
11.9
12.0
12.3
12.6
12.9
13.2
13.5
14.1
15.0
15.9
16.5
17.1
…
3BM1-9; for a 22 mm diameter shaft, 3BM1-22; etc.
Ring Free Diameter Tolerances: For ring sizes −8 through −20, +0.25, −0.13 mm; for sizes −21
through −26, +0.40, −0.25 mm; for sizes −27 through −38, +0.65, −0.50 mm; for sizes −40 through −
50, +0.90, −0.65 mm; for sizes −52 through −75, +1.00, −0.75 mm; for sizes −78 through −92, +1.40,
RETAINING RINGS
1687
−1.40 mm; for sizes −95 through −155, +1.65, −1.65 mm; for sizes −160 through −180, +2.05, −2.05
mm; and for sizes −185 through −250, +2.30, −2.30 mm.
Groove Diameter Tolerances: For ring sizes −8 and −9, +0.06 mm; for sizes −10 through −18,
+0.10 mm; for sizes −19 through − 28, +0.15 mm; for sizes −30 through −50, +0.20 mm; for sizes −
52 through −98, +0.30; for sizes −100 through −160, +0.40 mm; and for sizes −165 through −250,
+0.50 mm.
Groove Diameter F.I.M. (full indicator movement) or maximum allowable deviation of concentricity between groove and shaft: For ring sizes −8 through −10, 0.03 mm; for sizes −11 through −15,
0.05 mm; for sizes −16 through −25, 0.10 mm; for sizes −26 through −45, 0.15 mm; for sizes −46
through −80, 0.20 mm; for sizes −82 through −150, 0.25 mm; and for sizes −155 through −250, 0.30
mm.
Groove Width Tolerances: For ring size −8, +0.10 mm; for sizes −9 through −38, +0.15 mm; for
sizes −40 through −130, +0.20 mm; and for sizes −135 through −250, +0.25 mm.
Groove Maximum Bottom Radii: For ring sizes −8 through −17, 0.1 mm; for sizes −18 through −
30, 0.2 mm; for sizes −32 through −55, 0.3 mm; and for sizes −56 through −250, 0.4 mm.
For manufacturing details not shown, including materials, see ANSI B27.7-1977, R1993.
Table 3. American National Standard Metric Reduced Cross Section Retaining
Rings — E Ring External Series —3CM1 ANSI B27.7-1977, R1993
S
D
t
Y nom
G
W
d ref
Z min
S
D
t
Y nom
1
2
3
4
5
6
7
8
9
10
0.64
1.30
2.10
2.90
3.70
4.70
5.25
6.15
6.80
7.60
0.25
0.25
0.4
0.6
0.6
0.6
0.6
0.6
0.9
0.9
2.0
4.0
5.6
7.2
8.5
11.1
13.4
14.6
15.8
16.8
0.72
1.45
2.30
3.10
3.90
4.85
5.55
6.40
7.20
8.00
0.32
0.32
0.5
0.7
0.7
0.7
0.7
0.7
1.0
1.0
0.14
0.28
0.35
0.45
0.55
0.58
0.73
0.80
0.90
1.00
0.3
0.6
0.7
0.9
1.1
1.2
1.5
1.6
1.8
2.0
11
12
13
15
16
18
20
22
25
…
8.55
9.20
9.95
11.40
12.15
13.90
15.60
17.00
19.50
…
0.9
1.1
1.1
1.1
1.1
1.3
1.3
1.3
1.3
…
17.4
18.6
20.3
22.8
23.8
27.2
30.0
33.0
37.1
…
8.90
9.60
10.30
11.80
12.50
14.30
16.00
17.40
20.00
…
Edge
Margin
Depth
Dia.
G
Width
Groove
Outer
Dia.
Thickness
Free
Dia.
Shaft
Dia.
Edge
Margin
Ring
Depth
Dia.
Width
Groove
Outer
Dia.
Thickness
Free
Dia.
Shaft
Dia.
Ring
W
d ref
Z min
1.0
1.2
1.2
1.2
1.2
1.4
1.4
1.4
1.4
…
1.05
1.20
1.35
1.60
1.75
1.85
2.00
2.30
2.50
…
2.1
2.4
2.7
3.2
3.5
3.7
4.0
4.6
5.0
…
All dimensions are in millimeters. Size −1 is available in beryllium copper only.
3CM1-2; for a 13 mm shaft, 3CMI -13; etc.
Ring Free Diameter Tolerances: For ring sizes − 1 through −7, +0.03, −0.08 mm; for sizes −8
through −13, +0.05, −0.10 mm; and for sizes −15 through −25, +0.10, −0.15 mm.
Groove Diameter Tolerances: For ring sizes −1 and −2, −0.05 mm; for sizes −3 through −6, −0.08;
for sizes −7 through −11, −0.10 mm; for sizes −12 through −18, − 0.15 mm; and for sizes −20 through
−25, − 0.20 mm.
Groove Diameter F.I.M. (Full Indicator Movement) or maximum allowable deviation of concentricity between groove and shaft: For ring sizes −1 through −3, 0.04 mm; for −4 through −6, 0.05 mm;
for −7 through −10, 0.08 mm; for −11 through −25, 0.10 mm.
Groove Width Tolerances: For ring sizes − 1 and −2, +0.05 mm; for size −3, +0.10 mm; and for
sizes −4 through − 25, +0.15 mm.
Groove Maximum Bottom Radii: For ring sizes −1 and −2, 0.05 mm; for −3 through −7, 0.15 mm;
for −8 through −13, 0.25 mm; and for −15 through −25, 0.4 mm.
For manufacturing details not shown, including materials, see ANSI B27.7-1977, R1993.
1688
RETAINING RINGS
Ring Seated in Groove
Ring Expanded over Shaft
Table 4. American National Standard Metric Basic External Series
3AM1 Retaining Rings, Checking and Performance Data ANSI B27.7-1977, R1993
Ring
Series
and
Size No.
Clearance Dia.
Ring
Over
Shaft
Ring
in
Groove
Gaging
Diametera
Allowable Thrust Loads
Sharp Corner Abutment
Maximum
Allowable
Corner Radii
and Chamfers
Allowable
Assembly
Speedb
3AM1
C1
C2
K max
Prc
Pgd
R max
Ch max
…
No.
mm
mm
mm
kN
kN
mm
mm
rpm
−4a
7.0
6.8
4.90
0.6
0.2
0.35
0.25
70 000
−5a
8.2
7.9
5.85
1.1
0.3
0.35
0.25
70 000
−6a
9.1
8.8
6.95
1.4
0.4
0.35
0.25
70 000
−7
12.3
11.8
8.05
2.6
0.7
0.45
0.3
60 000
−8
13.6
13.0
9.15
3.1
1.0
0.5
0.35
55 000
−9
14.5
13.8
10.35
3.5
1.2
0.6
0.35
48 000
−10
15.5
14.7
11.50
3.9
1.5
0.7
0.4
42 000
−11
16.4
15.6
12.60
4.3
1.8
0.75
0.45
38 000
−12
17.4
16.6
13.80
4.7
2.0
0.8
0.45
34 000
−13
19.7
18.8
15.05
7.5
2.2
0.8
0.5
31 000
−14
20.7
19.7
15.60
8.1
2.6
0.9
0.5
28 000
−15
21.7
20.6
17.20
8.7
3.2
1.0
0.6
27 000
−16
22.7
21.6
18.35
9.3
3.5
1.1
0.6
25 000
−17
23.7
22.6
19.35
9.9
4.0
1.1
0.6
24 000
−18
26.2
25.0
20.60
16.0
4.4
1.2
0.7
23 000
−19
27.2
25.9
21.70
16.9
4.9
1.2
0.7
21 500
−20
28.2
26.8
22.65
17.8
5.7
1.2
0.7
20 000
−21
29.2
27.7
23.80
18.6
6.2
1.3
0.7
19 000
−22
30.3
28.7
24.90
19.6
7.0
1.3
0.8
18 500
−23
31.3
29.6
26.00
20.5
7.6
1.3
0.8
18 000
−24
34.1
32.4
27.15
21.4
8.2
1.4
0.8
17 500
−25
35.1
33.3
28.10
22.3
9.2
1.4
0.8
17 000
−26
36.0
34.2
29.25
23.2
9.6
1.5
0.9
16 500
−27
37.8
35.9
30.35
28.4
10.3
1.5
0.9
16 300
−28
38.8
36.9
31.45
28.4
11.0
1.6
1.0
15 800
−30
40.8
38.8
33.6
31.6
12.3
1.6
1.0
15 000
−32
42.8
40.7
35.9
33.6
14.1
1.7
1.0
14 800
−34
44.9
42.5
37.9
36
16.7
1.7
1.1
14 000
RETAINING RINGS
1689
Table 4. (Continued) American National Standard Metric Basic External Series
3AM1 Retaining Rings, Checking and Performance Data ANSI B27.7-1977, R1993
Ring
Series
and
Size No.
Clearance Dia.
Ring
Over
Shaft
Ring
in
Groove
Gaging
Diametera
Maximum
Allowable
Corner Radii
and Chamfers
Allowable
Assembly
Speedb
3AM1
C1
C2
K max
Prc
Pgd
R max
Ch max
…
No.
mm
mm
mm
kN
kN
mm
mm
rpm
−35
45.9
43.4
39.0
37
18.1
1.8
1.1
13 500
−36
48.6
46.1
40.2
38
18.9
1.9
1.2
13 300
−38
50.6
48.0
42.5
40
20.5
2.0
1.2
12 700
−40
54.0
51.3
44.5
52
22.6
2.1
1.2
12 000
−42
56.0
53.2
46.9
54
24.8
2.2
1.3
11 000
−43
57.0
54.0
47.9
55
26.4
2.3
1.4
10 800
−45
59.0
55.9
50.0
58
28.8
2.3
1.4
10 000
−46
60.0
56.8
50.9
59
30.4
2.4
1.4
9 500
−48
62.4
59.1
53.0
62
33
2.4
1.4
8 800
−50
64.4
61.1
55.2
64
35
2.4
1.4
8 000
−52
67.6
64.1
57.4
84
37
2.5
1.5
7 700
−54
69.6
66.1
59.5
87
40
2.5
1.5
7 500
−55
70.6
66.9
60.4
89
44
2.5
1.5
7 400
−57
72.6
68.9
62.7
91
45
2.6
1.5
7 200
−58
73.6
69.8
63.6
93
46
2.6
1.6
7 100
−60
75.6
71.8
65.8
97
49
2.6
1.6
7 000
−62
77.6
73.6
67.9
100
52
2.7
1.6
6 900
−65
80.6
76.6
71.2
105
54
2.8
1.7
6 700
−68
83.6
79.5
74.5
110
58
2.9
1.7
6 500
−70
88.1
83.9
76.4
136
62
2.9
1.7
6 400
−72
90.1
85.8
78.5
140
65
2.9
1.7
6 200
−75
93.1
88.7
81.7
147
69
3.0
1.8
5 900
−78
95.4
92.1
84.6
151
76
3.0
1.8
5 600
−80
97.9
93.1
87.0
155
80
3.1
1.9
5 400
−82
100.0
95.1
89.0
159
84
3.2
1.9
5 200
−85
103.0
97.9
92.1
165
91
3.2
1.9
5 000
−88
107.0
100.8
95.1
199
97
3.2
1.9
4 800
−90
109.0
103.6
97.1
204
101
3.2
1.9
4 500
−95
114.0
108.6
102.7
215
112
3.4
2.1
4 350
−100
119.5
113.7
108.0
227
123
3.5
2.1
4 150
a For checking when ring is seated in groove.
b These values have been calculated for steel rings.
c These values apply to rings made from SAE 1060–1090 steels and PH 15-7 Mo stainless steel used
on shafts hardened to Rc 50 minimum, with the exception of sizes −4, −5, and −6 which are supplied in
beryllium copper only. Values for other sizes made from beryllium copper can be calculated by multiplying the listed values by 0.75. The values listed include a safety factor of 4.
d These values are for all standard rings used on low carbon steel shafts. They include a safety factor
of 2.
Maximum allowable assembly loads with R max or Ch max are: For rings sizes −4, 0.2 kN; for
sizes −5 and −6, 0.5 kN; for sizes −7 through −12, 2.1 kN; for sizes −13 through −17, 4.0 kN; for sizes
−18 through −26, 6.0 kN; for sizes −27 through −38, 8.6 kN; for sizes −40 through − 50, 13.2 kN; for
sizes −52 through −68, 22.0 kN; for sizes −70 through −85, 32 kN; and for sizes −88 through −100,
47 kN.
Source: Appendix to American National Standard ANSI B27.7-1977, R1993.
1690
RETAINING RINGS
Table 5. American National Standard Metric Basic Internal Series 3BMI
Retaining Rings — Checking and Performance Data ANSI B27.7-1977, R1993
Max Allowable Radius
of Retained Part
Ring Compressed in Bore
Ring
Series and
Size No.
3BMI
No.
−8
−9
−10
−11
−12
−13
−14
−15
−16
−17
−18
−19
−20
−21
−22
−23
−24
−25
−26
−27
−28
−30
−32
−34
−35
−36
−37
−38
−40
−42
−45
−46
−47
−48
−50
−52
−55
−57
Clearance Dia.
Ring
Ring in
in Bore
Groove
C1
C2
mm
4.4
4.6
5.5
5.7
6.7
6.8
6.9
7.9
8.8
9.8
10.3
11.4
11.6
12.6
13.5
14.5
15.5
16.5
17.5
17.4
18.2
20.0
22.0
24.0
25.0
26.0
27.0
28.0
29.2
29.7
32.3
33.3
34.3
35.0
36.9
38.6
40.8
42.2
mm
4.8
5.0
6.0
6.3
7.3
7.5
7.7
8.7
9.7
10.8
11.3
12.5
12.7
13.8
14.8
15.9
16.9
18.1
19.2
19.2
20.0
21.9
23.9
26.1
27.2
28.3
29.3
30.4
31.6
32.2
34.9
36.0
37.1
37.9
40.0
41.9
44.2
45.7
Max Allowable Chamfer of Retained Part
Gaging
Diametera
A min
mm
1.40
1.50
1.85
1.95
2.25
2.35
2.65
2.80
2.80
3.35
3.40
3.40
3.8
4.2
4.3
4.9
5.2
6.0
5.7
5.9
6.0
6.0
7.3
7.6
8.0
8.3
8.4
8.6
9.7
9.0
9.6
9.7
10.0
10.5
12.1
11.7
11.9
12.5
Allowable Thrust Loads Sharp
Corner Abutment
Prb
Pgc
kN
2.4
4.4
4.9
5.4
5.8
8.9
9.7
10.4
11.0
11.7
12.3
13.1
13.7
14.5
22.5
23.5
24.8
25.7
26.8
33
34
37
39
42
43
44
45
46
62
65
69
71
72
74
77
99
105
109
kN
1.0
1.2
1.5
2.0
2.4
2.6
3.2
3.7
4.2
4.9
5.5
6.0
6.6
7.3
8.3
8.9
9.7
11.6
12.7
14.0
14.6
16.5
17.6
20.6
22.3
23.9
24.6
26.4
27.7
30.2
33.8
36
38
40
45
50
54
58
Maximum Allowable
Corner Radii
and Chamfers
R max
mm
0.4
0.5
0.5
0.6
0.6
0.7
0.7
0.7
0.7
0.75
0.75
0.8
0.9
0.9
0.9
1.0
1.0
1.0
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.7
1.7
1.7
1.7
1.7
1.7
1.7
2.0
2.0
2.0
Ch max
mm
0.3
0.35
0.35
0.4
0.4
0.5
0.5
0.5
0.5
0.6
0.6
0.65
0.7
0.7
0.7
0.8
0.8
0.8
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.6
1.6
1.6
RETAINING RINGS
1691
Table 5. (Continued) American National Standard Metric Basic Internal Series
3BMI
−58
−60
−62
−63
−65
−68
−70
−72
−75
−78
−80
−82
−85
−88
−90
−92
−95
−98
−100
−102
−105
−108
−110
−115
−120
−125
−130
−135
−140
−145
−150
−155
−160
−165
−170
−175
−180
−185
−190
−200
−210
−220
−230
−240
−250
43.2
45.5
47.0
47.8
49.4
52.0
53.8
55.9
58.2
61.2
63.0
63.5
66.8
69.6
71.6
73.6
76.7
78.3
80.3
82.2
85.1
88.1
88.4
93.2
98.2
103.1
108.0
110.4
115.3
120.4
125.3
130.4
133.8
138.7
143.6
146.0
151.4
154.7
159.5
169.2
177.5
184.1
194.0
200.4
210.0
46.8
49.3
50.8
51.7
53.4
56.2
58.2
60.4
62.9
66.0
68.0
68.7
72.2
75.2
77.3
79.4
82.7
84.5
86.6
88.6
91.6
94.7
95.1
100.1
105.2
110.2
115.2
117.7
122.7
127.9
132.9
138.1
141.6
146.6
151.6
154.2
159.8
163.3
168.3
178.2
186.9
194.1
204.6
211.4
221.4
13.0
12.7
14.0
14.2
14.2
14.4
16.1
17.4
16.8
17.6
17.2
18.8
19.1
20.4
21.4
22.2
22.6
22.6
24.1
25.5
26.0
26.4
27.5
29.4
27.2
30.3
31.0
30.4
30.4
31.6
33.5
37.0
35.0
33.1
38.2
37.7
39.0
37.3
35.0
43.9
40.6
38.3
49.0
45.4
53.0
111
115
119
120
149
156
161
166
172
209
215
220
228
236
241
247
255
263
269
273
281
290
295
309
321
335
349
415
429
444
460
475
613
632
651
670
690
851
873
919
965
1000
1060
1090
1150
60
66
68
71
75
82
88
93
101
108
115
122
131
141
147
153
164
174
181
187
196
205
212
227
241
255
269
283
298
313
327
343
359
374
390
403
434
457
480
517
566
608
686
725
808
2.0
2.0
2.0
2.0
2.0
2.3
2.3
2.3
2.3
2.5
2.5
2.6
2.6
2.8
2.8
2.9
3.0
3.0
3.1
3.2
3.3
3.5
3.6
3.7
3.9
4.0
4.0
4.3
4.3
4.3
4.3
4.3
4.5
4.6
4.6
4.8
5.0
5.1
5.3
5.4
5.8
6.1
6.3
6.6
6.7
1.6
1.6
1.6
1.6
1.6
1.8
1.8
1.8
1.8
2.0
2.0
2.1
2.1
2.2
2.2
2.4
2.5
2.5
2.5
2.6
2.6
2.7
2.8
2.9
3.1
3.2
3.2
3.4
3.4
3.4
3.4
3.4
3.6
3.7
3.7
3.8
4.0
4.1
4.3
4.3
4.6
4.9
5.1
5.3
5.4
a For checking when ring is seated in groove.
b These values apply to rings made from SAE 1060-1090 steels and PH 15-7 Mo stainless steel used
in bores hardened to Rc 50 minimum. Values for rings made from beryllium copper can be calculated
by multiplying the listed values by 0.75. The values listed include a safety factor of 4.
c These values are for standard rings used in low carbon steel bores. They include a safety factor of 2.
Maximum allowable assembly loads for R max or Ch max are: For ring size −8, 0.8 kN; for sizes −
9 through −12, 2.0 kN; for sizes −13 through −21, 4.0 kN; for sizes −22 through −26, 7.4 kN; for sizes
−27 through −38, 10.8 kN; for sizes −40 through −50, 17.4 kN; for sizes −52 through −63, 27.4 kN;
for size −65, 42.0 kN; for sizes −68 through −72, 39 kN; for sizes −75 through −130, 54 kN; for sizes
−135 through −155, 67 kN; for sizes −160 through −180, 102 kN; and for sizes −185 through −250,
151 kN.
1692
RETAINING RINGS
Table 6. American National Standard Metric E-Type External Series 3CM1
Retaining Rings — Checking and Performance Data ANSI B27.7-1977, R1993
Max. Allowable Radius of Retained Part
Ring
Series
and
Size No.
3CM1
No.
−1
−2
−3
−4
−5
−6
−7
−8
−9
−10
−11
−12
−13
−15
−16
−18
−20
−22
−25
Clearance
Diameter
Ring
in
Groove
C2
mm
2.2
4.3
6.0
7.6
8.9
11.5
14.0
15.1
16.5
17.5
18.0
19.3
21.0
23.5
24.5
27.9
30.7
33.7
37.9
Max. Allowable Chamfer of Retained Part
Maximum
Allowable
Corner Radii
and Chamfers
Pr b
Pgc
kN
0.06
0.13
0.3
0.7
0.9
1.1
1.2
1.4
3.0
3.4
3.7
4.9
5.4
6.2
6.6
8.7
9.8
10.8
12.2
R max
mm
0.4
0.8
1.1
1.6
1.6
1.6
1.6
1.7
1.7
1.7
1.7
1.9
2.0
2.0
2.0
2.1
2.2
2.2
2.4
kN
0.02
0.09
0.17
0.3
0.4
0.6
0.8
1.0
1.3
1.6
1.9
2.3
2.9
4.0
4.5
5.4
6.5
8.1
10.1
Allowable
Assembly
Speeda
…
rpm
40 000
40 000
34 000
31 000
27 000
25 000
23 000
21 500
19 500
18 000
16 500
15 000
13 000
11 500
10 000
9 000
8 000
7 000
5 000
Ch max
mm
0.25
0.5
0.7
1.2
1.2
1.2
1.2
1.3
1.3
1.3
1.3
1.4
1.5
1.5
1.5
1.6
1.7
1.7
1.9
a These values have been calculated for steel rings.
b These values apply to rings made from SAE 1060-1090 steels and PH 15-7 Mo stainless steel used
on shafts hardened to Rc 50 minimum, with the exception of size −1 which is supplied in beryllium
copper only. Values for other sizes made from beryllium copper can be calculated by multiplying the
listed values by 0.75. The values listed include a safety factor of 4.
c These values apply to all standard rings used on low carbon steel shafts. They include a safety factor
of 2.
Maximum allowable assembly loads with R max or Ch max are as follows:
Ring Size
No.
Maximum
Allowable Load,kN
Ring Size
No.
Maximum
AllowableLoad, kN
Ring Size
No.
Maximum
AllowableLoad, kN
−1
−2
−3
−4
−5
−6
−7
0.06
0.13
0.3
0.7
0.9
1.1
1.2
−8
−9
−10
−11
−12
−13
−15
1.4
3.0
3.4
3.7
4.9
5.4
6.2
−16
−18
−20
−22
−25
…
…
6.6
8.7
9.8
10.8
12.2
…
…
RETAINING RINGS
;;;
;;
;;;
;;
;;;
;;
;;;
;;
;;;
;;
;;;
;;
1693
SIZE
0.500 to 1.500
G
SIZE
1.562 and UP
A
C
F
E
D
Table 7. Medium Duty Internal Spiral Retaining Rings MIL-R-27426
Ring
Groove
Static Thrust
Load (lb)
Bore
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
0.500
0.512
0.531
0.562
0.594
0.625
0.656
0.687
0.718
0.750
0.777
0.781
0.812
0.843
0.866
0.875
0.906
0.938
0.968
0.987
1.000
1.023
1.031
1.062
1.093
1.125
1.156
1.188
1.218
1.250
1.281
1.312
1.343
1.375
1.406
1.437
1.456
1.468
1.500
1.562
1.574
1.625
1.653
1.687
1.750
1.813
0.532
0.544
0.564
0.594
0.626
0.658
0.689
0.720
0.751
0.790
0.817
0.821
0.853
0.889
0.913
0.922
0.949
0.986
1.025
1.041
1.054
1.078
1.084
1.117
1.147
1.180
1.210
1.249
1.278
1.312
1.342
1.374
1.408
1.442
1.472
1.504
1.523
1.535
1.567
1.634
1.649
1.701
1.730
1.768
1.834
1.894
0.045
0.045
0.045
0.045
0.045
0.045
0.045
0.045
0.045
0.065
0.065
0.065
0.065
0.065
0.065
0.065
0.065
0.065
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.085
0.085
0.085
0.085
0.085
0.085
0.095
0.095
0.095
0.095
0.095
0.095
0.108
0.108
0.108
0.108
0.118
0.118
0.118
0.526
0.538
0.557
0.588
0.619
0.651
0.682
0.713
0.744
0.782
0.808
0.812
0.843
0.880
0.903
0.912
0.939
0.975
1.015
1.030
1.043
1.066
1.074
1.104
1.135
1.167
1.198
1.236
1.266
1.298
1.329
1.360
1.395
1.427
1.458
1.489
1.508
1.520
1.552
1.617
1.633
1.684
1.712
1.750
1.813
1.875
0.030
0.030
0.030
0.030
0.030
0.030
0.030
0.030
0.030
0.036
0.036
0.036
0.036
0.036
0.036
0.036
0.036
0.036
0.042
0.042
0.042
0.042
0.042
0.042
0.042
0.042
0.042
0.048
0.048
0.048
0.048
0.048
0.048
0.048
0.048
0.048
0.048
0.048
0.048
0.056
0.056
0.056
0.056
0.056
0.056
0.056
2000
2050
2130
2250
2380
2500
2630
2750
2870
3360
3480
3500
3640
3780
3880
3920
4060
4200
4340
4420
4480
5470
5510
5680
5840
6010
6180
7380
7570
7770
7960
8150
8340
8540
8740
8930
9050
9120
9320
10100
10180
10510
10690
10910
11310
11720
Ring
Groove
Static Thrust
Load (lb)
Groove
Bore
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
Groove
405
420
455
495
535
610
670
725
790
800
835
840
915
1155
1250
1250
1335
1430
1950
1865
1910
1660
1650
1745
1820
1935
2020
2115
2195
2510
2425
2532
2875
3070
3180
3330
3410
3460
3605
3590
3640
3875
4020
4510
4895
5080
3.437
3.500
3.543
3.562
3.625
3.687
3.740
3.750
3.812
4.437
4.500
4.527
4.562
4.625
4.687
4.724
4.750
4.812
4.875
4.921
4.937
5.000
5.118
5.125
5.250
5.375
5.500
5.511
5.625
5.708
5.750
5.875
5.905
6.000
6.125
6.250
6.299
6.375
6.500
6.625
6.692
6.750
6.875
7.000
7.086
7.125
3.574
3.636
3.684
3.703
3.769
3.832
3.885
3.894
3.963
4.611
4.674
4.701
4.737
4.803
4.867
4.903
4.930
4.993
5.055
5.102
5.122
5.185
5.304
5.311
5.436
5.566
5.693
5.703
5.818
5.909
5.950
6.077
6.106
6.202
6.349
6.474
6.524
6.601
6.726
6.863
6.931
6.987
7.114
7.239
7.337
7.376
0.188
0.188
0.198
0.198
0.198
0.198
0.198
0.198
0.208
0.238
0.238
0.238
0.238
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.312
0.312
0.312
0.312
0.312
0.312
0.312
0.312
0.312
0.312
0.312
0.312
0.312
3.543
3.606
3.653
3.672
3.737
3.799
3.852
3.862
3.930
4.573
4.636
4.663
4.698
4.765
4.827
4.864
4.890
4.952
5.015
5.061
5.081
5.144
5.262
5.269
5.393
5.522
5.647
5.658
5.772
5.861
5.903
6.028
6.058
6.153
6.297
6.422
6.471
6.547
6.672
6.807
6.874
6.932
7.057
7.182
7.278
7.317
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
27660
28170
28520
28670
29180
29680
30100
30180
30680
35710
36220
36440
36720
43940
44530
44880
45130
45710
46310
46750
46900
47500
48620
48690
49880
51050
52250
52350
53440
54230
54630
55810
56100
57000
69500
70920
71480
72340
73760
75180
75940
76590
78010
79430
80410
80850
18240
18575
19515
19620
20330
20675
20975
21030
22525
30215
30645
30830
31065
32420
32855
33115
33300
33735
34175
34495
35595
36050
36905
36955
37590
39565
40485
40565
41405
43730
44050
45010
45240
45965
52750
53825
54250
54905
55980
60375
60985
61515
62655
63790
68125
68500
1694
RETAINING RINGS
Table 7. (Continued) Medium Duty Internal Spiral Retaining Rings MIL-R-27426
Bore
Dia.
A
1.850
1.875
1.938
2.000
2.047
2.062
2.125
2.165
2.188
2.250
2.312
2.375
2.437
2.440
2.500
2.531
2.562
2.625
2.677
2.688
2.750
2.813
2.834
2.875
2.937
2.952
3.000
3.062
3.125
3.149
3.187
3.250
3.312
3.346
3.375
Ring
Dia.
G
1.937
1.960
2.025
2.091
2.138
2.154
2.217
2.260
2.284
2.347
2.413
2.476
2.543
2.546
2.606
2.641
2.673
2.736
2.789
2.803
2.865
2.929
2.954
2.995
3.058
3.073
3.122
3.186
3.251
3.276
3.311
3.379
3.446
3.479
3.509
Groove
Wall
E
0.118
0.118
0.118
0.128
0.128
0.128
0.128
0.138
0.138
0.138
0.138
0.138
0.148
0.148
0.148
0.148
0.148
0.148
0.158
0.158
0.158
0.158
0.168
0.168
0.168
0.168
0.168
0.168
0.178
0.178
0.178
0.178
0.188
0.188
0.188
Dia.
C
1.917
1.942
2.005
2.071
2.118
2.132
2.195
2.239
2.262
2.324
2.390
2.453
2.519
2.522
2.582
2.617
2.648
2.711
2.767
2.778
2.841
2.903
2.928
2.969
3.031
3.046
3.096
3.158
3.223
3.247
3.283
3.350
3.416
3.450
3.479
Width
D
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
Static Thrust
Load (lb)
Ring
11960
12120
12530
12930
13230
13330
13740
14000
14150
14550
14950
15350
15760
15780
16160
16360
16560
16970
17310
17380
17780
18190
18320
18590
18990
19090
24150
24640
25150
25340
25650
26160
26660
26930
27160
Groove
5735
5825
6250
7090
7275
7225
7450
8020
8105
8335
9030
9275
10005
10015
10625
10900
11030
11305
12065
12115
12530
12675
13340
13530
13825
13890
14420
14720
15335
15450
15640
16270
17245
17425
17575
Bore
Dia.
A
7.250
7.375
7.480
7.500
7.625
7.750
7.875
8.000
8.250
8.267
8.464
8.500
8.750
8.858
9.000
9.055
9.250
9.448
9.500
9.750
10.000
10.250
10.500
10.750
11.000
3.875
3.938
4.000
4.063
4.125
4.188
4.250
4.312
4.330
4.375
Ring
Dia.
G
7.501
7.628
7.734
7.754
7.890
8.014
8.131
8.266
8.528
8.546
8.744
8.780
9.041
9.151
9.293
9.359
9.555
9.755
9.806
10.068
10.320
10.582
10.834
11.095
11.347
4.025
4.089
4.157
4.222
4.284
4.347
4.416
4.479
4.497
4.543
Wall
E
0.312
0.312
0.312
0.312
0.312
0.312
0.312
0.312
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.375
0.208
0.208
0.218
0.218
0.218
0.218
0.228
0.228
0.228
0.228
Groove
Dia.
C
7.442
7.567
7.672
7.692
7.827
7.952
8.077
8.202
8.462
8.479
8.676
8.712
8.972
9.080
9.222
9.287
9.482
9.680
9.732
9.992
10.242
10.502
10.752
11.012
11.262
3.993
4.056
5.124
4.187
4.249
4.311
4.380
4.442
4.460
4.505
Width
D
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.094
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
Static Thrust
Load (lb)
Ring
82270
83690
84880
85110
86520
87940
89360
90780
93620
93810
96040
96450
99290
100520
102130
102750
104960
107210
107800
110640
113470
116310
119150
121980
124820
30680
31700
32190
32700
33200
33710
34210
34710
34850
32210
Groove
69700
70900
71910
72105
77125
78390
79655
80920
87575
87755
89850
90230
97265
98465
100045
105190
107455
109755
110360
118145
121175
129340
132490
141030
144310
22525
23265
24835
25225
25610
25795
27665
28065
28185
28475
Source: Spirolox Retaining Rings, RR Series. All dimensions are in inches. Depth of groove d = (C
− A)/2. Standard material: carbon spring steel (SAE 1070-1090).
Ring Thickness, F: For shaft sizes 0.500 through 0.718, 0.025; for sizes 0.750 through 0.938, 0.031;
for sizes 0.968 through 1.156, 0.037; for sizes 1.188 through 1.500, 0.043; for sizes 1.562 through
2.952, 0.049; for sizes 3.000 through 4.562, 0.061; for sizes 4.625 through 6.000, 0.072; for sizes
6.125 through 11.000, 0.086.
Ring Free Diameter Tolerances: For housing sizes 0.500 through 1.031, +0.013, −0.000; for sizes
1.062 through 1.500, +0.015, −0.000; for sizes 1.562 through 2.047, +0.020, −0.000; for sizes 2.062
through 3.000, +0.025, −0.000; for sizes 3.062 through 4.063, +0.030, −0.000; for sizes 4.125
through 7.125, +0.055, −0.000; for sizes 7.250 through 11.000, +0.065, −0.000.
Ring Thickness Tolerances: Thickness indicated is for unplated rings; add 0.002 to upper thickness
tolerance for plated rings. For housing sizes 0.500 through 1.500, ±0.002; for sizes 1.562 through
4.562, ±0.003; for sizes 4.625 through 11.000, ±0.004.
Groove Diameter Tolerances: For housing sizes 0.500 through 0.750, ±0.002; for sizes 0.777
through 1.031, ±0.003; for sizes 1.062 through 1.500, ±0.004; for sizes 1.562 through 2.047, ±0.005;
for sizes 2.062 through 5.125, ±0.006; for sizes 5.250 through 6.000, ±0.007; for sizes 6.125 through
11.000, ±0.008.
Groove Width Tolerances: For housing sizes 0.500 through 1.156, +0.003, −0.000; for sizes 1.188
through 11.000, +0.006, −0.000.
RETAINING RINGS
1695
Table 8. Medium Duty External Spiral Retaining Rings MIL-R-27426
;
;
;
;
;
;
SIZE
0.500 to 1.500
G
SIZE
1.562 and UP
C
A
F
E
D
Ring
Groove
Static Thrust
Load (lb)
Ring
Groove
Static Thrust
Load (lb)
Groove
Shaft
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
Groove
550
3.343
3.210
0.188
3.239
0.068
26910
17410
640
3.375
3.242
0.188
3.271
0.068
27160
17570
2210
700
3.437
3.301
0.188
3.331
0.068
27660
18240
0.030
2250
730
3.500
3.363
0.188
3.394
0.068
28170
18580
0.569
0.030
2380
740
3.543
3.402
0.198
3.433
0.068
28520
19510
0.055
0.594
0.030
2500
970
3.562
3.422
0.198
3.452
0.068
28670
19620
0.617
0.055
0.625
0.030
2630
1020
3.625
3.483
0.198
3.515
0.068
29180
19970
0.669
0.629
0.055
0.638
0.030
2680
1040
3.687
3.543
0.198
3.575
0.068
29680
20680
0.687
0.647
0.055
0.656
0.030
2750
1060
3.740
3.597
0.198
3.628
0.068
30100
20970
0.718
0.679
0.055
0.687
0.030
2870
1110
3.750
3.606
0.198
3.638
0.068
30180
21030
0.750
0.710
0.065
0.719
0.036
3360
1100
3.812
3.668
0.198
3.700
0.068
30680
21380
0.781
0.741
0.065
0.750
0.036
3500
1210
3.875
3.724
0.208
3.757
0.068
31190
22890
0.812
0.771
0.065
0.781
0.036
3640
1260
3.938
3.784
0.208
3.820
0.068
31700
23270
0.843
0.803
0.065
0.812
0.036
3780
1310
4.000
3.842
0.218
3.876
0.068
32190
24840
0.875
0.828
0.065
0.838
0.036
3920
1620
4.063
3.906
0.218
3.939
0.068
32700
25230
0.906
0.860
0.065
0.869
0.036
4060
1680
4.125
3.967
0.218
4.000
0.068
33200
25820
0.937
0.889
0.065
0.900
0.036
4200
1740
4.134
3.975
0.218
4.010
0.068
33270
25670
0.968
0.916
0.075
0.925
0.042
5180
2080
4.188
4.030
0.218
4.058
0.068
33710
27260
0.984
0.930
0.075
0.941
0.042
5260
2120
4.250
4.084
0.228
4.120
0.068
34210
27660
1.000
0.946
0.075
0.957
0.042
5350
2150
4.312
4.147
0.218
4.182
0.068
34710
28070
1.023
0.968
0.075
0.980
0.042
5470
2200
4.331
4.164
0.218
4.200
0.068
34860
28410
1.031
0.978
0.075
0.988
0.042
5510
2220
4.375
4.208
0.218
4.245
0.068
35210
28480
1.062
1.007
0.075
1.020
0.042
5680
2230
4.437
4.271
0.218
4.307
0.068
35710
28880
1.093
1.040
0.075
1.051
0.042
5840
2300
4.500
4.326
0.238
4.364
0.068
36220
30640
1.125
1.070
0.075
1.083
0.042
6010
2370
4.562
4.384
0.250
4.422
0.079
43340
31980
1.156
1.102
0.075
1.114
0.042
6180
2430
4.625
4.447
0.250
4.485
0.079
43940
32420
1.188
1.127
0.085
1.140
0.048
7380
2850
4.687
4.508
0.250
4.457
0.079
44530
32860
1.218
1.159
0.085
1.170
0.048
7570
2930
4.724
4.546
0.250
4.584
0.079
44880
33120
1.250
1.188
0.085
1.202
0.048
7770
3000
4.750
4.571
0.250
4.610
0.079
45130
33300
1.281
1.221
0.085
1.233
0.048
7960
3080
4.812
4.633
0.250
4.672
0.079
45710
33730
1.312
1.251
0.095
1.264
0.048
8150
3150
4.875
4.695
0.250
4.735
0.079
46310
34170
1.343
1.282
0.095
1.295
0.048
8340
3230
4.937
4.757
0.250
4.797
0.079
46900
34610
1.375
1.308
0.095
1.323
0.048
8540
3580
5.000
4.820
0.250
4.856
0.079
47500
36050
1.406
1.340
0.095
1.354
0.048
8740
3660
5.118
4.934
0.250
4.974
0.079
48620
36900
1.437
1.370
0.095
1.385
0.048
8930
3740
5.125
4.939
0.250
4.981
0.079
48690
36950
1.468
1.402
0.095
1.416
0.048
9120
3820
5.250
5.064
0.250
5.107
0.079
49880
37590
1.500
1.433
0.095
1.448
0.048
9320
3910
5.375
5.187
0.250
5.228
0.079
51060
39560
1.562
1.490
0.108
1.507
0.056
10100
4300
5.500
5.308
0.250
5.353
0.079
52250
40480
1.575
1.503
0.108
1.520
0.056
10190
4340
5.511
5.320
0.250
5.364
0.079
52350
40560
1.625
1.549
0.108
1.566
0.056
10510
4800
5.625
5.433
0.250
5.478
0.079
53440
41400
Shaft
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
0.500
0.467
0.045
0.474
0.030
2000
0.531
0.498
0.045
0.505
0.030
2130
0.551
0.518
0.045
0.525
0.030
0.562
0.529
0.045
0.536
0.594
0.561
0.045
0.625
0.585
0.656
1696
RETAINING RINGS
Table 8. (Continued) Medium Duty External Spiral Retaining Rings MIL-R-27426
1.687
1.610
0.118
1.628
0.056
10910
4980
5.750
5.550
0.250
5.597
0.079
54630
44050
1.750
1.673
0.118
1.691
0.056
11310
5170
5.875
5.674
0.250
5.722
0.079
55810
45010
1.771
1.690
0.118
1.708
0.056
11450
5590
5.905
5.705
0.250
5.752
0.079
56100
45240
1.813
1.730
0.118
1.749
0.056
11720
5810
6.000
5.798
0.250
5.847
0.079
57000
45970
1.875
1.789
0.128
1.808
0.056
12120
6290
6.125
5.903
0.312
5.953
0.094
69500
52750
1.938
1.844
0.128
1.861
0.056
12530
7470
6.250
6.026
0.312
6.078
0.094
70920
53830
1.969
1.882
0.128
1.902
0.056
12730
6610
6.299
6.076
0.312
6.127
0.094
71480
54250
2.000
1.909
0.128
1.992
0.056
12930
7110
6.375
6.152
0.312
6.203
0.094
72340
54900
2.062
1.971
0.128
2.051
0.056
13330
7870
6.500
6.274
0.312
6.328
0.094
73760
55980
2.125
2.029
0.128
2.082
0.056
13740
7990
6.625
6.390
0.312
6.443
0.094
75180
60380
2.156
2.060
0.138
2.091
0.056
13940
8020
6.750
6.513
0.312
6.568
0.094
76590
61515
2.188
2.070
0.138
2.113
0.056
14150
8220
6.875
6.638
0.312
6.693
0.094
78010
62650
2.250
2.092
0.138
2.176
0.056
14550
8340
7.000
6.761
0.312
6.818
0.094
79430
63790
2.312
2.153
0.138
2.234
0.056
14950
9030
7.125
6.877
0.312
6.933
0.094
80850
68500
2.362
2.211
0.138
2.284
0.056
15270
9230
7.250
6.999
0.312
7.058
0.094
82270
69700
2.375
2.273
0.138
2.297
0.056
15350
9280
7.375
7.125
0.312
7.183
0.094
83690
70900
2.437
2.331
0.148
2.355
0.056
15760
10000
7.500
7.250
0.312
7.308
0.094
85110
72100
2.500
2.394
0.148
2.418
0.056
16160
10260
7.625
7.363
0.312
7.423
0.094
86520
77120
2.559
2.449
0.148
2.473
0.056
16540
11020
7.750
7.486
0.312
7.548
0.094
87940
78390
2.562
2.452
0.148
2.476
0.056
16560
11030
7.875
7.611
0.312
7.673
0.094
89360
79650
2.625
2.514
0.148
2.539
0.056
16970
11300
8.000
7.734
0.312
7.798
0.094
90780
80920
2.688
2.572
0.158
2.597
0.056
17380
12250
8.250
7.972
0.375
8.038
0.094
93620
87580
2.750
2.635
0.158
2.660
0.056
17780
12390
8.500
8.220
0.375
8.288
0.094
96450
90230
2.813
2.696
0.168
2.722
0.056
18190
12820
8.750
8.459
0.375
8.528
0.094
99290
97270
2.875
2.755
0.168
2.781
0.056
18590
13530
9.000
8.707
0.375
8.778
0.094
102130
100050
2.937
2.817
0.168
2.843
0.056
18990
13820
9.250
8.945
0.375
9.018
0.094
104960
107560
2.952
2.831
0.168
2.858
0.056
19090
13890
9.500
9.194
0.375
9.268
0.094
107800
110360
3.000
2.877
0.168
2.904
0.068
24150
14420
9.750
9.432
0.375
9.508
0.094
110640
118150
3.062
2.938
0.168
2.966
0.068
24640
14720
10.000
9.680
0.375
9.758
0.094
113470
121180
3.125
3.000
0.178
3.027
0.068
25150
15335
10.250
9.918
0.375
9.998
0.094
116310
129340
3.149
3.023
0.178
3.051
0.068
25340
15450
10.500
10.166
0.375
10.248
0.094
119150
132490
3.187
3.061
0.178
3.089
0.068
25650
15640
10.750
10.405
0.375
10.488
0.094
121980
141030
3.250
3.121
0.178
3.150
0.068
26160
16270
11.000
10.653
0.375
10.738
0.094
124820
144310
3.312
3.180
0.188
3.208
0.068
26660
17250
Source: Spirolox Retaining Rings, RS Series. All dimensions are in inches. Depth of groove d = (A
− C)/2. Standard material: carbon spring steel (SAE 1070–1090).
Ring Thickness, F: For shaft sizes 0.500 through 0.718, 0.025; for sizes 0.750 through 0.937, 0.031;
for sizes 0.968 through 1.156, 0.037; for sizes 1.188 through 1.500, 0.043; for sizes 1.562 through
2.952, 0.049; for sizes 3.000 through 4.500, 0.061; for sizes 4.562 through 6.000, 0.072; for sizes
6.125 through 11.000, 0.086.
Ring Free Diameter Tolerances: For shaft sizes 0.500 through 1.031, +0.000, + 0.000, −0.013; for
sizes 1.062 through 1.500, +0.000, −0.015; for sizes 1.562 through 2.125, +0.000, −0.020; for sizes
Ring Thickness Tolerances: Thickness indicated is for unplated rings; add 0.002 to upper tolerance
for plated rings. For shaft sizes 0.500 through 1.500, ± 0.002; for sizes 1.562 through 4.500, ± 0.003;
for sizes 4.562 through 11.000, ± 0.004.
Groove Diameter Tolerances: For shaft sizes 0.500 through 0.562, ±0.002; for sizes 0.594 through
1.031, ± 0.003; for sizes 1.062 through 1.500, ± 0.004; for sizes 1.562 through 2.000, ± 0.005; for
sizes 2.062 through 5.125, ±0.006; for sizes 5.250 through 6.000, ± 0.007; for sizes 6.125 through
11.000, ± 0.008.
Groove Width Tolerances: For shaft sizes 0.500 through 1.156, +0.003, −0.000; for sizes 1.188
through 11.000, +0.006, −0.000.
RETAINING RINGS
;;
;;
;;
;;
;;
;;
1697
SIZE
0.500 to 0.750
G
SIZE
0.777 and UP
A
C
F
E
D
Table 9. Heavy Duty Internal Spiral Retaining Rings MIL-R-27426
Ring
Groove
Static Thrust
Load (lb)
Ring
Groove
Static Thrust
Load (lb)
Groove
Bore
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
Groove
310
3.543
3.781
0.281
3.755
0.120
49420
28250
2590
325
3.562
3.802
0.281
3.776
0.120
49680
28815
0.039
2840
455
3.625
3.868
0.281
3.841
0.120
50560
30160
0.655
0.039
3160
655
3.750
4.002
0.312
3.974
0.120
52310
33720
0.065
0.732
0.039
3480
965
3.875
4.136
0.312
4.107
0.120
54050
37250
0.807
0.065
0.796
0.039
3790
1065
3.938
4.203
0.312
4.174
0.120
54930
39045
0.777
0.836
0.075
0.825
0.046
4720
1026
4.000
4.270
0.312
4.240
0.120
55790
41025
0.812
0.873
0.075
0.862
0.046
4930
1150
4.125
4.369
0.312
4.339
0.120
57540
38495
0.866
0.931
0.075
0.920
0.046
5260
1395
4.250
4.501
0.312
4.470
0.120
59280
41955
0.875
0.943
0.085
0.931
0.046
5310
1520
4.330
4.588
0.312
4.556
0.120
60400
44815
0.901
0.972
0.085
0.959
0.046
5470
1675
4.500
4.768
0.312
4.735
0.120
62770
50290
0.938
1.013
0.085
1.000
0.046
5690
1925
4.625
4.899
0.312
4.865
0.120
64510
54155
1.000
1.080
0.085
1.066
0.046
6070
2310
4.750
5.030
0.312
4.995
0.120
66260
58270
1.023
1.105
0.085
1.091
0.046
6210
2480
5.000
5.297
0.312
5.260
0.120
69740
65095
1.062
1.138
0.103
1.130
0.056
7010
1940
5.250
5.559
0.350
5.520
0.139
83790
68315
1.125
1.205
0.103
1.197
0.056
7420
2280
5.375
5.690
0.350
5.650
0.139
85780
72840
1.188
1.271
0.103
1.262
0.056
7840
2615
5.500
5.810
0.350
5.770
0.139
87780
74355
1.250
1.339
0.103
1.330
0.056
8250
3110
5.750
6.062
0.350
6.020
0.139
91770
77735
1.312
1.406
0.118
1.396
0.056
8650
3650
6.000
6.314
0.350
6.270
0.139
95760
81120
1.375
1.471
0.118
1.461
0.056
9070
4075
6.250
6.576
0.380
6.530
0.174
122520
80655
1.439
1.539
0.118
1.528
0.056
9490
4670
6.500
6.838
0.380
6.790
0.174
127420
90295
1.456
1.559
0.118
1.548
0.056
9600
4890
6.625
6.974
0.380
6.925
0.174
129870
92060
1.500
1.605
0.118
1.594
0.056
9900
5275
6.750
7.105
0.380
7.055
0.174
132320
102475
1.562
1.675
0.128
1.658
0.068
12780
4840
7.000
7.366
0.380
7.315
0.174
137220
110410
1.625
1.742
0.128
1.725
0.068
13290
5415
7.250
7.628
0.418
7.575
0.209
170370
103440
1.653
1.772
0.128
1.755
0.068
13520
5695
7.500
7.895
0.418
7.840
0.209
176240
115780
1.688
1.810
0.128
1.792
0.068
13810
6070
7.750
8.157
0.418
8.100
0.209
182120
127270
1.750
1.876
0.128
1.858
0.068
14320
7635
8.000
8.419
0.418
8.360
0.209
187990
139370
1.812
1.940
0.128
1.922
0.068
14820
7305
8.250
8.680
0.437
8.620
0.209
193870
152695
1.850
1.981
0.158
1.962
0.068
15130
7960
8.500
8.942
0.437
8.880
0.209
199740
161735
1.875
2.008
0.158
1.989
0.068
15340
8305
8.750
9.209
0.437
9.145
0.209
205620
173065
1.938
2.075
0.158
2.056
0.068
15850
9125
9.000
9.471
0.437
9.405
0.209
211490
182515
2.000
2.142
0.158
2.122
0.068
16360
10040
9.250
9.737
0.437
9.669
0.209
217370
194070
2.062
2.201
0.168
2.186
0.086
21220
8280
9.500
10.000
0.500
9.930
0.209
223240
204550
Bore
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
0.500
0.538
0.045
0.530
0.039
2530
0.512
0.550
0.045
0.542
0.039
0.562
0.605
0.055
0.596
0.625
0.675
0.055
0.688
0.743
0.750
1698
RETAINING RINGS
Table 9. (Continued) Heavy Duty Internal Spiral Retaining Rings MIL-R-27426
Ring
Groove
Static Thrust
Load (lb)
Ring
Groove
Static Thrust
Load (lb)
Groove
Bore
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
Groove
8935
9.750
10.260
0.500
10.189
0.209
229120
214325
22520
9745
10.000
10.523
0.500
10.450
0.209
234990
225330
23160
10455
10.250
10.786
0.500
10.711
0.209
240870
236605
0.086
23790
11700
10.500
11.047
0.500
10.970
0.209
246740
247110
2.517
0.086
24440
12715
10.750
11.313
0.500
11.234
0.209
252620
260530
0.200
2.584
0.086
25110
13550
11.000
11.575
0.500
11.495
0.209
258490
272645
2.667
0.200
2.648
0.086
25730
14640
11.250
11.838
0.500
11.756
0.209
264360
285040
2.531
2.700
0.200
2.681
0.086
26050
15185
11.500
12.102
0.562
12.018
0.209
270240
298285
2.562
2.733
0.225
2.714
0.103
29940
12775
11.750
12.365
0.562
12.279
0.209
276120
311240
2.625
2.801
0.225
2.781
0.103
30680
13780
12.000
12.628
0.562
12.540
0.209
281990
324475
2.688
2.868
0.225
2.848
0.103
31410
14775
12.250
12.891
0.562
12.801
0.209
287860
337980
2.750
2.934
0.225
2.914
0.103
32140
15790
12.500
13.154
0.562
13.063
0.209
293740
352390
2.813
3.001
0.225
2.980
0.103
32870
16845
12.750
13.417
0.562
13.324
0.209
299610
366460
2.834
3.027
0.225
3.006
0.103
33120
17595
13.000
13.680
0.662
13.585
0.209
305490
380805
2.875
3.072
0.225
3.051
0.103
33600
18505
13.250
13.943
0.662
13.846
0.209
311360
395430
3.000
3.204
0.225
3.182
0.103
35060
20795
13.500
14.207
0.662
14.108
0.209
317240
411000
3.062
3.271
0.281
3.248
0.120
42710
18735
13.750
14.470
0.662
14.369
0.209
323110
426185
3.125
3.338
0.281
3.315
0.120
43590
19865
14.000
14.732
0.662
14.630
0.209
328990
441645
3.157
3.371
0.281
3.348
0.120
44020
20345
14.250
14.995
0.662
14.891
0.209
334860
457380
3.250
3.470
0.281
3.446
0.120
45330
22120
14.500
15.259
0.750
15.153
0.209
340740
474120
3.346
3.571
0.281
3.546
0.120
46670
23905
14.750
15.522
0.750
15.414
0.209
346610
490415
3.469
3.701
0.281
3.675
0.120
48390
26405
15.000
15.785
0.750
15.675
0.209
352490
506990
3.500
3.736
0.281
3.710
0.120
48820
27370
Bore
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
2.125
2.267
0.168
2.251
0.086
21870
2.188
2.334
0.168
2.318
0.086
2.250
2.399
0.168
2.382
0.086
2.312
2.467
0.200
2.450
2.357
2.535
0.200
2.440
2.602
2.500
Source: Spirolox Retaining Rings, RRN Series. All dimensions are in inches. Depth of groove d =
(C − A)/2. Thickness indicated is for unplated rings; add 0.002 to upper thickness tolerance for plated
rings. Standard material: carbon spring steel (SAE 1070–1090).
Ring Thickness, F: For housing sizes 0.500 through 0.750, 0.035; for sizes 0.777 through 1.023,
0.042; for sizes 1.062 through 1.500, 0.050; for sizes 1.562 through 2.000, 0.062; for sizes 2.062
through 2.531, 0.078; for sizes 2.562 through 3.000, 0.093; for sizes 3.062 through 5.000, 0.111; for
sizes 5.250 through 7.000, 0.156; for sizes 7.250 through 15.000, 0.187.
1.562 through 2.000, +0.020, −0.000; for sizes 2.062 through 2.531, + 0.025, −0.000; for sizes 2.562
through 6.000, +0.050, −0.000; for sizes 6.250 through 7.000, +0.055. −0.000; for sizes 7.250
through 15.000, +0.140, −0.000.
Ring Thickness Tolerances: For housing sizes 0.500 through 1.500, ± 0.002; for sizes 1.562
through 5.000, ± 0.003; for sizes 5.250 through 6.000, ± 0.004; for sizes 6.250 through 15.000, ±
0.005.
Groove Diameter Tolerances: For housing sizes 0.500 through 0.750, ± 0.002; for sizes 0.777
through 1.023, ± 0.003; for sizes 1.062 through 1.500, ± 0.004; for sizes 1.562 through 2.000, ±
0.005; for sizes 2.062 through 5.000, ± 0.006; for sizes 5.250 through 6.000, ± 0.007; for sizes 6.250
through 10.500, ± 0.008; for sizes 10.750 through 12.500, ± 0.010; for sizes 12.750 through 15.000,
± 0.012.
Groove Width Tolerances: For housing sizes 0.500 through 1.023, +0.003, −0.000; for sizes 1.062
through 15.000, +0.008, −0.000.
RETAINING RINGS
;;
;;
;;
;;
;;
;;
1699
SIZE
0.469 to 0.669
G
SIZE
0.688 and UP
C
A
F
E
D
Table 10. Heavy Duty External Spiral Retaining Rings MIL-R-27426
Ring
Groove
Static Thrust
Load (lb)
Shaft
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
0.469
0.500
0.551
0.562
0.594
0.625
0.669
0.688
0.750
0.781
0.812
0.875
0.938
0.984
1.000
1.023
1.062
1.125
1.188
1.250
1.312
1.375
1.438
1.500
1.562
1.625
1.687
1.750
1.771
1.812
1.875
1.969
2.000
2.062
2.125
2.156
2.250
2.312
2.375
2.437
2.500
2.559
2.625
2.687
0.439
0.464
0.514
0.525
0.554
0.583
0.623
0.641
0.698
0.727
0.756
0.814
0.875
0.919
0.932
0.953
0.986
1.047
1.105
1.163
1.218
1.277
1.336
1.385
1.453
1.513
1.573
1.633
1.651
1.690
1.751
1.838
1.867
1.932
1.989
2.018
2.105
2.163
2.223
2.283
2.343
2.402
2.464
2.523
0.045
0.050
0.050
0.050
0.050
0.055
0.055
0.065
0.065
0.065
0.065
0.075
0.075
0.085
0.085
0.085
0.103
0.103
0.103
0.103
0.118
0.118
0.118
0.118
0.128
0.128
0.128
0.128
0.128
0.128
0.158
0.158
0.158
0.168
0.168
0.168
0.168
0.168
0.200
0.200
0.200
0.200
0.200
0.200
0.443
0.468
0.519
0.530
0.559
0.588
0.629
0.646
0.704
0.733
0.762
0.821
0.882
0.926
0.940
0.961
0.998
1.059
1.118
1.176
1.232
1.291
1.350
1.406
1.468
1.529
1.589
1.650
1.669
1.708
1.769
1.857
1.886
1.946
2.003
2.032
2.120
2.178
2.239
2.299
2.360
2.419
2.481
2.541
0.029
0.039
0.039
0.039
0.039
0.039
0.039
0.046
0.046
0.046
0.046
0.046
0.046
0.046
0.046
0.046
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.068
0.086
0.086
0.086
0.086
0.086
0.086
0.086
0.086
0.086
0.086
0.086
1880
2530
2790
2840
3000
3160
3380
4170
4550
4740
4930
5310
5690
5970
6070
6210
7010
7420
7840
8250
8650
9070
9490
9900
12780
13290
13800
14320
14490
14820
15340
16110
16360
21220
21870
22190
23160
23790
24440
25080
25730
26340
27020
27650
Ring
Groove
Static Thrust
Load (lb)
Groove
Shaft
Dia.
A
Dia.
G
Wall
E
Dia.
C
Width
D
Ring
Groove
510
440
540
560
700
820
1070
960
1250
1430
1620
2000
2440
2790
2950
3170
2810
2890
3450
4110
4810
5650
6340
7060
6600
7330
8190
8760
9040
9440
9950
11040
11420
11820
12980
13390
14650
15510
16170
16840
17530
17940
18930
19640
3.500
3.543
3.625
3.687
3.750
3.875
3.938
4.000
4.250
4.375
4.500
4.750
5.000
5.250
5.500
5.750
6.000
6.250
6.500
6.750
7.000
7.250
7.500
7.750
8.000
8.250
8.500
8.750
9.000
9.250
9.500
9.750
10.000
10.250
10.500
10.750
11.000
11.250
11.500
11.750
12.000
12.250
12.500
12.750
3.293
3.333
3.411
3.469
3.527
3.647
3.708
3.765
4.037
4.161
4.280
4.518
4.756
4.995
5.228
5.466
5.705
5.938
6.181
6.410
6.648
6.891
7.130
7.368
7.606
7.845
8.083
8.324
8.560
8.798
9.036
9.275
9.508
9.745
9.984
10.221
10.459
10.692
10.934
11.171
11.410
11.647
11.885
12.124
0.270
0.270
0.270
0.270
0.270
0.270
0.270
0.270
0.270
0.270
0.270
0.270
0.270
0.350
0.350
0.350
0.350
0.418
0.418
0.418
0.418
0.418
0.437
0.437
0.437
0.437
0.437
0.437
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.562
0.562
0.562
0.562
0.562
0.562
3.316
3.357
3.435
3.493
3.552
3.673
3.734
3.792
4.065
4.190
4.310
4.550
4.790
5.030
5.265
5.505
5.745
5.985
6.225
6.465
6.705
6.942
7.180
7.420
7.660
7.900
8.140
8.383
8.620
8.860
9.100
9.338
9.575
9.814
10.054
10.293
10.533
10.772
11.011
11.250
11.490
11.729
11.969
12.208
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.139
0.139
0.139
0.139
0.174
0.174
0.174
0.174
0.174
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
0.209
48820
49420
50560
51430
52310
54050
54930
55790
59280
61020
62770
66260
69740
83790
87780
91770
95760
122520
127420
132320
137220
142130
176240
182120
187990
193870
199740
205620
211490
217370
223240
229120
234990
240870
246740
252620
258490
264360
270240
276120
281990
287860
293740
299610
32250
33000
34490
35820
37180
39190
40230
41660
39370
40530
42810
47570
52580
57830
64720
70540
76610
82930
89510
96330
103400
111810
120170
128060
136200
144590
153220
160800
171250
180640
190280
201140
212810
223780
234490
246000
257230
269270
281590
294180
306450
319580
332360
346030
1700
RETAINING RINGS
Table 10. (Continued) Heavy Duty External Spiral Retaining Rings MIL-R-27426
Shaft
Dia.
A
2.750
2.875
2.937
3.000
3.062
3.125
3.156
3.250
3.344
3.437
Ring
Dia.
G
2.584
2.702
2.760
2.818
2.878
2.936
2.965
3.054
3.144
3.234
Groove
Wall
E
0.225
0.225
0.225
0.225
0.225
0.225
0.225
0.225
0.225
0.225
Dia.
C
2.602
2.721
2.779
2.838
2.898
2.957
2.986
3.076
3.166
3.257
Width
D
0.103
0.103
0.103
0.103
0.103
0.103
0.103
0.103
0.103
0.103
Static Thrust
Load (lb)
Ring
32140
33600
34320
35060
35780
36520
36880
37980
39080
40170
Groove
20380
22170
23240
24340
25140
26290
26860
28320
29800
30980
Shaft
Dia.
A
13.000
13.250
13.500
13.750
14.000
14.250
14.500
14.750
15.000
Ring
Dia.
G
12.361
12.598
12.837
13.074
13.311
13.548
13.787
14.024
14.262
Wall
E
0.662
0.662
0.662
0.662
0.662
0.662
0.750
0.750
0.750
Groove
Static Thrust
Load (lb)
Dia. Width
C
D
Ring
Groove
12.448 0.209 305490 359330
12.687 0.209 311360 373530
12.927 0.209 317240 387340
13.166 0.209 323110 402090
13.405 0.209 328990 417110
13.644 0.209 334860 432410
13.884 0.209 340740 447250
14.123 0.209 346610 463090
14.363 0.209 352490 478450
Source: Spirolox Retaining Rings, RSN Series. All dimensions are in inches. Depth of groove d =
(A − C)/2. Thickness indicated is for unplated rings; add 0.002 to upper tolerance for plated rings.
Standard material: carbon spring steel (SAE 1070-1090).
Ring Thickness, F: For shaft size 0.469, 0.025; for sizes 0.500 through 0.669, 0.035; for sizes 0.688
through 1.023, 0.042; for sizes 1.062 through 1.500, 0.050; for sizes 1.562 through 2.000, 0.062; for
sizes 2.062 through 2.687, 0.078; for sizes 2.750 through 3.437, 0.093; for sizes 3.500 through 5.000,
0.111; for sizes 5.250 through 6.000, 0.127; for sizes 6.250 through 7.250, 0.156; for sizes 7.500
through 15.000, 0.187.
Ring Free Diameter Tolerances: For shaft sizes 0.469 through 1.500, +0.000, −0.013; for sizes
1.562 through 2.000, +0.000, −0.020; for sizes 2.062 through 2.687, + 0.000, −0.025; for sizes 2.750
through 15.000, +0.000, −0.110.
Ring Thickness Tolerances: For shaft sizes 0.469 through 1.500, ±0.002; for sizes 1.562 through
5.000, ±0.003; for sizes 5.250 through 6.000, ±0.004; for sizes 6.250 through 15.000, ±0.005.
Groove Diameter Tolerances: For shaft sizes 0.469 through 0.562, ±0.002; for sizes 0.594 through
1.023, ±0.003; for sizes 1.062 through 1.500, ±0.004; for sizes 1.562 through 2.000, ±0.005; for sizes
2.062 through 5.000, ±0.006; for sizes 5.250 through 6.000, ±0.007; for sizes 6.250 through 10.000,
±0.008; for sizes 10.250 through 12.500, ±0.010; for sizes 12.750 through 15.000, ±0.012.
through 6.000, +0.006; −0.000; for sizes 6.250 through 7.250, + 0.008, −0.000; for sizes 7.500
through 15.000, +0.008, −0.000.
Thrust Load Capacity: The most important criterion in determining which ring is best
suited for a specific application is thrust load capacity. The strength of the retaining ring
and groove must both be considered when analyzing the thrust load capacity of an application to determine whether the groove or the retaining ring is likely to fail first. When a
retaining ring application fails, the fault will usually be with the groove, unless the groove
material is of very high strength.
Ring Material: The standard materials for spiral-wound retaining rings are SAE 1070 to
1090 carbon spring steels and 18-8 type 302 stainless steels. The 1070 to 1090 carbon
spring steels provide high-strength retaining rings at low cost. Type 302 stainless steel
withstands ordinary rusting. Other materials are used for specialized applications, such as
the type 316 stainless frequently used in the food industry. For high-temperature use,
superalloy A286 rings can be used at up to 900°F and Inconel X-750 at up to 1200°F. Other
materials, such as 316 stainless steel, 17-7PH and Inconel stainless steels are sometimes
used for special-purpose and custom-made rings. Standard ring are typically supplied
uncoated, however, special finishes such as cadmium, phosphate, zinc, or black oxide
coatings for carbon spring steel rings and passivation of stainless steel rings are available.
RETAINING RINGS
1701
Table 11. Important Dimensions of Inch Series External Retaining Rings
MS 16624
A
;;
;;
;;
L
GD
S
U
H
Shaft
Dia.
D
0.125
0.156
0.188
0.197
0.219
0.236
0.250
0.276
0.281
0.312
0.344
0.354
0.375
0.394
0.406
0.438
0.469
0.500
0.551
0.562
0.594
0.625
0.669
0.672
0.688
0.750
0.781
0.812
0.844
0.875
0.938
0.984
1.000
1.023
1.062
1.125
1.188
1.250
1.312
1.375
1.438
1.500
1.562
1.625
1.687
1.750
1.772
Ring
Dia.
Thick.
A
T
0.112
0.010
0.142
0.010
0.168
0.015
0.179
0.015
0.196
0.015
0.215
0.015
0.225
0.025
0.250
0.025
0.256
0.025
0.281
0.025
0.309
0.025
0.320
0.025
0.338
0.025
0.354
0.025
0.366
0.025
0.395
0.025
0.428
0.025
0.461
0.035
0.509
0.035
0.521
0.035
0.550
0.035
0.579
0.035
0.621
0.035
0.621
0.035
0.635
0.042
0.693
0.042
0.722
0.042
0.751
0.042
0.780
0.042
0.810
0.042
0.867
0.042
0.910
0.042
0.925
0.042
0.946
0.042
0.982
0.050
1.041
0.050
1.098
0.050
1.156
0.050
1.214
0.050
1.272
0.050
1.333
0.050
1.387
0.050
1.446
0.062
1.503
0.062
1.560
0.062
1.618
0.062
1.637
0.062
Lugs: D = 0.125 to 0.236
Dia.
G
0.117
0.146
0.175
0.185
0.205
0.222
0.230
0.255
0.261
0.290
0.321
0.330
0.352
0.369
0.382
0.412
0.443
0.468
0.519
0.530
0.559
0.588
0.629
0.631
0.646
0.704
0.733
0.762
0.791
0.821
0.882
0.926
0.940
0.961
0.998
1.059
1.118
1.176
1.232
1.291
1.350
1.406
1.468
1.529
1.589
1.650
1.669
Groove
Width
W
0.012
0.012
0.018
0.018
0.018
0.018
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.039
0.039
0.039
0.039
0.039
0.039
0.039
0.046
0.046
0.046
0.046
0.046
0.046
0.046
0.046
0.046
0.046
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.056
0.068
0.068
0.068
0.068
0.068
;;;
;;;
;;;
;;;
;;;
W
T
Margin
E
0.012
0.015
0.018
0.018
0.021
0.021
0.030
0.030
0.030
0.033
0.033
0.036
0.036
0.036
0.036
0.039
0.039
0.048
0.048
0.048
0.051
0.054
0.060
0.060
0.063
0.069
0.072
0.075
0.080
0.081
0.084
0.087
0.090
0.093
0.096
0.099
0.105
0.111
0.120
0.126
0.132
0.141
0.141
0.144
0.147
0.150
0.153
Shaft
Dia.
D
1.812
1.875
1.969
2.000
2.062
2.125
2.156
2.250
2.312
2.375
2.438
2.500
2.559
2.625
2.688
2.750
2.875
2.938
3.000
3.062
3.125
3.156
3.250
3.346
3.438
3.500
3.543
3.625
3.688
3.750
3.875
3.938
4.000
4.250
4.375
4.500
4.750
5.000
5.250
5.500
5.750
6.000
6.250
6.500
6.750
7.000
7.500
E
Lugs: D = 4.25 to 8.00
Ring
Dia.
Thick.
A
T
1.675
0.062
1.735
0.062
1.819
0.062
1.850
0.062
1.906
0.078
1.964
0.078
1.993
0.078
2.081
0.078
2.139
0.078
2.197
0.078
2.255
0.078
2.313
0.078
2.377
0.078
2.428
0.078
2.485
0.078
2.543
0.093
2.659
0.093
2.717
0.093
2.775
0.093
2.832
0.093
2.892
0.093
2.920
0.093
3.006
0.093
3.092
0.093
3.179
0.093
3.237
0.109
3.277
0.109
3.352
0.109
3.410
0.109
3.468
0.109
3.584
0.109
3.642
0.109
3.700
0.109
3.989
0.109
4.106
0.109
4.223
0.109
4.458
0.109
4.692
0.109
4.927
0.125
5.162
0.125
5.396
0.125
5.631
0.125
5.866
0.156
6.100
0.156
6.335
0.156
6.570
0.156
7.009
0.187
Dia.
G
1.708
1.769
1.857
1.886
1.946
2.003
2.032
2.120
2.178
2.239
2.299
2.360
2.419
2.481
2.541
2.602
2.721
2.779
2.838
2.898
2.957
2.986
3.076
3.166
3.257
3.316
3.357
3.435
3.493
3.552
3.673
3.734
3.792
4.065
4.190
4.310
4.550
4.790
5.030
5.265
5.505
5.745
5.985
6.225
6.465
6.705
7.180
Groove
Width
W
0.068
0.068
0.068
0.068
0.086
0.086
0.086
0.086
0.086
0.086
0.086
0.086
0.086
0.086
0.086
0.103
0.103
0.103
0.103
0.103
0.103
0.103
0.103
0.103
0.103
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.120
0.139
0.139
0.139
0.139
0.174
0.174
0.174
0.174
0.209
Margin
E
0.156
0.159
0.168
0.171
0.174
0.183
0.186
0.195
0.201
0.204
0.207
0.210
0.210
0.216
0.219
0.222
0.231
0.237
0.243
0.246
0.252
0.255
0.261
0.270
0.270
0.276
0.279
0.285
0.291
0.297
0.303
0.306
0.312
0.276
0.276
0.285
0.300
0.315
0.330
0.351
0.366
0.381
0.396
0.411
0.426
0.441
0.480
1702
RETAINING RINGS
Source: Industrial Retaining Rings, 3100 Series. All dimensions are in inches. Depth of groove d =
(D − G)/2. Thickness indicated is for unplated rings; for most plated rings, the maximum ring thickness will not exceed the minimum groove width (W) minus 0.0002 inch. Standard material: carbon
spring steel (SAE 1060-1090).
through 6.000, +0.020, −0.040; for sizes 6.250 through 6.750, +0.020, −0.050; for sizes 7.000 and
7.500, +0.050, −0.130.
Ring Thickness Tolerances: For shaft sizes 0.125 and 0.156, ±0.001; for sizes 0.188 through 1.500,
±0.002; for sizes 1.562 through 5.000, ±0.003; for sizes 5.250 through 6.000, ±0.004; for sizes 6.250
through 7.500, ±0.005.
Groove Diameter Tolerances: For shaft sizes 0.125 through 0.250, ±0.0015; for sizes 0.276
through 0.562, ±0.002; for sizes 0.594 through 1.023, ±0.003; for sizes 1.062 though 1.500, ±0.004;
for sizes 1.562 through 2.000, ±0.005; for sizes 2.062 through 5.000, ±0.006; for sizes 5.250 through
through 7.500, +0.008, −0.000.
A
T
L
S
U
H
;;;
;;;
;;;
;;;
;;;
;;;
;;;
;;
;
W
Lugs: D = 2.062 to 2.750
D = 3.000 to 4.625
DG
E
Table 12. Important Dimensions of Inch Series Internal Retaining Rings
Ring
Groove
Ring
Groove
Housing
Dia.
D
Dia.
A
Thick.
T
Dia.
G
Width
W
Margin
E
Housing
Dia.
D
Dia.
A
Thick.
T
Dia.
G
Width
W
Margin
E
0.250
0.280
0.015
0.268
0.018
0.027
2.500
2.775
0.078
2.648
0.086
0.222
0.312
0.346
0.015
0.330
0.018
0.027
2.531
2.775
0.078
2.681
0.086
0.225
0.375
0.415
0.025
0.397
0.029
0.033
2.562
2.844
0.093
2.714
0.103
0.228
0.438
0.482
0.025
0.461
0.029
0.036
2.625
2.910
0.093
2.781
0.103
0.234
0.453
0.498
0.025
0.477
0.029
0.036
2.677
2.980
0.093
2.837
0.103
0.240
0.500
0.548
0.035
0.530
0.039
0.045
2.688
2.980
0.093
2.848
0.103
0.240
0.512
0.560
0.035
0.542
0.039
0.045
2.750
3.050
0.093
2.914
0.103
0.246
0.562
0.620
0.035
0.596
0.039
0.051
2.812
3.121
0.093
2.980
0.103
0.252
0.625
0.694
0.035
0.665
0.039
0.060
2.835
3.121
0.093
3.006
0.103
0.255
0.688
0.763
0.035
0.732
0.039
0.066
2.875
3.191
0.093
3.051
0.103
0.264
0.750
0.831
0.035
0.796
0.039
0.069
2.953
3.325
0.093
3.135
0.103
0.273
0.777
0.859
0.042
0.825
0.046
0.072
3.000
3.325
0.093
3.182
0.103
0.273
0.812
0.901
0.042
0.862
0.046
0.075
3.062
3.418
0.109
3.248
0.120
0.279
0.866
0.961
0.042
0.920
0.046
0.081
3.125
3.488
0.109
3.315
0.120
0.285
0.875
0.971
0.042
0.931
0.046
0.084
3.149
3.523
0.109
3.341
0.120
0.288
0.901
1.000
0.042
0.959
0.046
0.087
3.156
3.523
0.109
3.348
0.120
0.288
0.938
1.041
0.042
1.000
0.046
0.093
3.250
3.623
0.109
3.446
0.120
0.294
1.000
1.111
0.042
1.066
0.046
0.099
3.346
3.734
0.109
3.546
0.120
0.300
1.023
1.136
0.042
1.091
0.046
0.102
3.469
3.857
0.109
3.675
0.120
0.309
1.062
1.180
0.050
1.130
0.056
0.102
3.500
3.890
0.109
3.710
0.120
0.315
RETAINING RINGS
1703
Table 12. (Continued) Important Dimensions of Inch Series Internal Retaining Rings
Ring
Groove
Ring
Groove
Housing
Dia.
D
Dia.
A
Thick.
T
Dia.
G
Width
W
Margin
E
Housing
Dia.
D
Dia.
A
Thick.
T
Dia.
G
Width
W
Margin
E
1.125
1.249
0.050
1.197
0.056
0.108
3.543
3.936
0.109
3.755
0.120
0.318
1.181
1.319
0.050
1.255
0.056
0.111
3.562
3.936
0.109
3.776
0.120
0.321
1.188
1.319
0.050
1.262
0.056
0.111
3.625
4.024
0.109
3.841
0.120
0.324
1.250
1.388
0.050
1.330
0.056
0.120
3.740
4.157
0.109
3.964
0.120
0.336
1.259
1.388
0.050
1.339
0.056
0.120
3.750
4.157
0.109
3.974
0.120
0.336
1.312
1.456
0.050
1.396
0.056
0.126
3.875
4.291
0.109
4.107
0.120
0.348
1.375
1.526
0.050
1.461
0.056
0.129
3.938
4.358
0.109
4.174
0.120
0.354
1.378
1.526
0.050
1.464
0.056
0.129
4.000
4.424
0.109
4.240
0.120
0.360
1.438
1.596
0.050
1.528
0.056
0.135
4.125
4.558
0.109
4.365
0.120
0.360
1.456
1.616
0.050
1.548
0.056
0.138
4.250
4.691
0.109
4.490
0.120
0.360
1.500
1.660
0.050
1.594
0.056
0.141
4.331
4.756
0.109
4.571
0.120
0.360
1.562
1.734
0.062
1.658
0.068
0.144
4.500
4.940
0.109
4.740
0.120
0.360
1.575
1.734
0.062
1.671
0.068
0.144
4.625
5.076
0.109
4.865
0.120
0.360
1.625
1.804
0.062
1.725
0.068
0.150
4.724
5.213
0.109
4.969
0.120
0.366
1.653
1.835
0.062
1.755
0.068
0.153
4.750
5.213
0.109
4.995
0.120
0.366
1.688
1.874
0.062
1.792
0.068
0.156
5.000
5.485
0.109
5.260
0.120
0.390
1.750
1.942
0.062
1.858
0.068
0.162
5.250
5.770
0.125
5.520
0.139
0.405
1.812
2.012
0.062
1.922
0.068
0.165
5.375
5.910
0.125
5.650
0.139
0.405
1.850
2.054
0.062
1.962
0.068
0.168
5.500
6.066
0.125
5.770
0.139
0.405
1.875
2.054
0.062
1.989
0.068
0.171
5.750
6.336
0.125
6.020
0.139
0.405
1.938
2.141
0.062
2.056
0.068
0.177
6.000
6.620
0.125
6.270
0.139
0.405
2.000
2.210
0.062
2.122
0.068
0.183
6.250
6.895
0.156
6.530
0.174
0.420
2.047
2.280
0.078
2.171
0.086
0.186
6.500
7.170
0.156
6.790
0.174
0.435
2.062
2.280
0.078
2.186
0.086
0.186
6.625
7.308
0.156
6.925
0.174
0.450
2.125
2.350
0.078
2.251
0.086
0.189
6.750
7.445
0.156
7.055
0.174
0.456
2.165
2.415
0.078
2.295
0.086
0.195
7.000
7.720
0.156
7.315
0.174
0.471
2.188
2.415
0.078
2.318
0.086
0.195
7.250
7.995
0.187
7.575
0.209
0.486
2.250
2.490
0.078
2.382
0.086
0.198
7.500
8.270
0.187
7.840
0.209
0.510
2.312
2.560
0.078
2.450
0.086
0.207
7.750
8.545
0.187
8.100
0.209
0.525
2.375
2.630
0.078
2.517
0.086
0.213
8.000
8.820
0.187
8.360
0.209
0.540
2.440
2.702
0.078
2.584
0.086
0.216
8.250
9.095
0.187
8.620
0.209
0.555
(G − D)/2. Thickness indicated is for unplated rings. Standard material: carbon spring steel (SAE
1060-1090).
0.812 through 1.023, +0.015, − 0.010; for sizes 1.062 through 1.500, + 0.025, − 0.020; for sizes 1.562
for sizes 7.250 through 8.250, ±0.090.
Ring Thickness Tolerances: For housing sizes 0.250 through 1.500, ±0.002; for sizes 1.562
through 5.000, ±0.003; for sizes 5.250 through 6.000, ±0.004; for sizes 6.250 through 8.250, ±0.005.
Groove Diameter Tolerances: For housing sizes 0.250 and 0.312, ±0.001; for sizes 0.375 through
0.750, ±0.002; for sizes 0.777 through 1.023 ±0.003; for sizes 1.062 through 1.500, ±0.004; for sizes
1.562 through 2.000, ±0.005; for sizes 2.047 through 5.000 ±0.006; for sizes 5.250 through 6.000,
±0.007; for sizes 6.250 through 8.250, ±0.008.
Groove Width Tolerances: For housing sizes 0.250 and 0.312, +0.002, − 0.000; for sizes 0.375
through 5.000, +0.005; −0.000; for sizes 5.250 through 6.000, +0.006, −0.000; for sizes 6.250
through 8.250, +0.008, −0.000.
1704
RETAINING RINGS
;;
;;
Table 13. Important Dimensions of Inch Series External Retaining Rings MS16632
L
AB
T
Shaft
Diameter
D
0.125
0.156
0.188
0.219
0.236
0.250
0.281
0.312
0.375
0.406
0.437
0.500
0.562
0.625
0.687
0.750
0.812
0.875
0.937
1.000
1.125
1.188
1.250
1.375
1.500
1.750
2.000
Free Dia.
A
0.102
0.131
0.161
0.187
0.203
0.211
0.242
0.270
0.328
0.359
0.386
0.441
0.497
0.553
0.608
0.665
0.721
0.777
0.830
0.887
0.997
1.031
1.110
1.220
1.331
1.555
1.777
Ring
Thickness
T
0.015
0.015
0.015
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.035
0.035
0.035
0.042
0.042
0.042
0.042
0.042
0.042
0.050
0.050
0.050
0.050
0.050
0.062
0.062
Diameter
B
0.164
0.205
0.245
0.275
0.295
0.311
0.344
0.376
0.448
0.485
0.516
0.581
0.653
0.715
0.780
0.845
0.915
0.987
1.054
1.127
1.267
1.321
1.410
1.550
1.691
1.975
2.257
Diameter
G
0.106
0.135
0.165
0.193
0.208
0.220
0.247
0.276
0.335
0.364
0.393
0.450
0.507
0.563
0.619
0.676
0.732
0.789
0.843
0.900
1.013
1.047
1.126
1.237
1.350
1.576
1.800
;;;
;;;
;;;
;;;
;;;
W
GD
E
Groove
Width
W
0.018
0.018
0.018
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.039
0.039
0.039
0.046
0.046
0.046
0.046
0.046
0.046
0.056
0.056
0.056
0.056
0.056
0.068
0.068
aStatic
Margin
E
0.020
0.020
0.022
0.026
0.028
0.030
0.034
0.036
0.040
0.042
0.044
0.050
0.056
0.062
0.068
0.074
0.080
0.086
0.094
0.100
0.112
0.140
0.124
0.138
0.150
0.174
0.200
Thrust
Load (lb)
Ring
Groove
85
40
110
55
130
70
260
100
280
115
295
130
330
170
370
200
440
265
480
300
515
340
825
440
930
550
1030
690
1700
820
1850
985
2010
1150
2165
1320
2320
1550
2480
1770
3300
2200
3500
2900
3600
2700
4000
3300
4400
4000
6400
5300
7300
7000
a Thrust Load Safety Factors: Ring, 4; groove, 2. Groove wall thrust loads are for grooves machined
in cold-rolled steel with a tensile yield strength of 45,000 psi; for other shaft materials, the thrust load
varies proportionally with the yield strength.
(D − G)/2. Standard material: carbon spring steel (SAE 1060-1090). Thickness indicated is for
unplated rings; for most plated rings with shaft sizes less than 1.000 inch, the maximum thickness
will not exceed the minimum groove width (W) minus 0.0002 inch; for larger rings, the ring thickness may increase by 0.002 inch.
Groove Maximum Bottom Radii: For shaft diameters less than 0.500 inch, 0.005 inch; for shaft
sizes 0.500 through 1.000 inch, 0.010 inch; all larger sizes, 0.015 inch.
0.219 through 0.437, +0.003, −0.005; for sizes 0.500 through 0.625, ±0.006; for sizes 0.687 through
1.000, ±0.007; for sizes 1.125 through 1.500, ±0.008; for sizes 1.750 and 2.000, ±0.010.
Ring Thickness Tolerances: For shaft sizes 0.125 through 1.500, ±0.002; for sizes 1.750 and 2.000,
±0.003.
Groove Diameter Tolerances: For shaft sizes 0.125 through 0.188, ±0.0015; for sizes 0.219
for sizes 1.750 and 2.000, ±0.005.
RETAINING RINGS
1705
;;;
;;;
;;;
;;;
Table 14. Important Dimensions of Inch Series External Retaining Rings MS16633
W
A B
GD
E
T
Shaft
Diameter
D
0.040
0.062
0.062a
0.062b
0.094
0.094
0.110
0.125
0.140
0.140c
0.140d
0.156
0.172
0.188
0.188
0.218
0.250
0.312
0.375
0.437
0.437
0.500
0.625
0.744
0.750
0.750
0.875
0.985
1.000
1.188
1.375
Free Dia.
A
0.025
0.051
0.051
0.051
0.073
0.069
0.076
0.094
0.100
0.108
0.102
0.114
0.125
0.145
0.122
0.185
0.207
0.243
0.300
0.337
0.375
0.392
0.480
0.616
0.616
0.574
0.668
0.822
0.822
1.066
1.213
Ring
Thickness
T
0.010
0.010
0.010
0.020
0.015
0.015
0.015
0.015
0.015
0.015
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.035
0.035
0.035
0.042
0.042
0.050
0.050
0.050
0.050
0.050
0.050
0.062
0.062
Diameter
B
0.079
0.140
0.156
0.187
0.187
0.230
0.375
0.230
0.203
0.250
0.270
0.282
0.312
0.335
0.375
0.437
0.527
0.500
0.660
0.687
0.600
0.800
0.940
1.000
1.000
1.120
1.300
1.500
1.500
1.626
1.875
Diameter
G
0.026
0.052
0.052
0.052
0.074
0.074
0.079
0.095
0.102
0.110
0.105
0.116
0.127
0.147
0.125
0.188
0.210
0.250
0.303
0.343
0.380
0.396
0.485
0.625
0.625
0.580
0.675
0.835
0.835
1.079
1.230
Groove
Width
W
0.012
0.012
0.012
0.023
0.018
0.018
0.018
0.018
0.018
0.018
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.039
0.039
0.039
0.046
0.046
0.056
0.056
0.056
0.056
0.056
0.056
0.068
0.068
Margin
E
0.014
0.010
0.010
0.010
0.020
0.020
0.030
0.030
0.038
0.030
0.034
0.040
0.044
0.040
0.062
0.030
0.040
0.062
0.072
0.094
0.058
0.104
0.140
0.118
0.124
0.170
0.200
0.148
0.164
0.108
0.144
aStatic Thrust
Load (lb)
Ring
Groove
13
7
20
7
20
7
40
7
45
20
45
20
55
40
65
45
70
60
70
45
150
55
165
70
180
90
195
90
195
135
225
75
260
115
325
225
685
315
800
485
800
290
1100
600
1370
1040
1940
1050
1960
1100
1960
1500
2200
2050
2570
1710
2620
1900
3400
1500
4100
2300
a Thrust Load Safety Factors: Ring 3; groove, 2.
(D − G)/2. Standard material: carbon spring steel (SAE 1060 –1090). Thickness indicated is for
unplated rings; for most plated rings with shaft sizes less than 0.625, the maximum ring thickness
will not exceed the minimum groove width (W) minus 0.0002 inch; for larger rings, the thickness
may increase by 0.002 inch.
Groove Maximum Bottom Radii: For shaft sizes 0.040 and 0.062, 0.003 inch; for sizes 0.094
through 0.250, 0.005 inch; for sizes 0.312 through 0.437, 0.010 inch; for sizes 0.500 through 1.375,
0.015 inch.
and 1.375, +0.006, −0.010.
Ring Thickness Tolerances: For shaft sizes 0.040 and 0.062a, ±0.001; for sizes 0.062b through
1.000, ±0.002; for sizes 1.188 and 1.375, ±0.003.
Groove Diameter Tolerances: For shaft sizes 0.040 through 0.218, +0.002, −0.000; for sizes 0.250
through 1.000, +0.003, −0.000; for sizes 1.188 and 1.375, +0.005, −0.000.
Grove Width Tolerances: For shaft sizes 0.040 through 0.140c, +0.002, −0.000; for sizes 0.140d
through 1.000, +0.003, −0.000; for sizes 1.188 and 1.375, +0.004, −0.000.
1706
RETAINING RINGS
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Table 15. Dimensions of Inch Series External Retaining Rings MS3215
W
A B
GD
E
T
Ring
Groove
a Static
Shaft
Diameter
D
Free Dia.
A
Thickness
T
Diameter
B
Diameter
G
Width
W
Margin
E
0.094
0.125
0.156
0.188
0.219
0.250
0.312
0.312
0.375
0.438
0.500
0.562
0.072
0.093
0.113
0.143
0.182
0.204
0.242
0.242
0.292
0.332
0.385
0.430
0.015
0.015
0.025
0.025
0.025
0.025
0.025
0.035
0.035
0.035
0.042
0.042
0.206
0.270
0.335
0.375
0.446
0.516
0.588
0.588
0.660
0.746
0.810
0.870
0.074
0.095
0.116
0.147
0.188
0.210
0.250
0.250
0.303
0.343
0.396
0.437
0.018
0.018
0.029
0.029
0.029
0.029
0.029
0.039
0.039
0.039
0.046
0.046
0.020
0.030
0.040
0.040
0.031
0.040
0.062
0.062
0.072
0.096
0.104
0.124
Thrust
Load (lb)
Ring
55
75
150
180
215
250
300
420
520
600
820
930
Groove
13
25
40
50
50
75
135
135
190
285
360
480
a Thrust Load Safety Factors: Ring, 3; groove, 2.
unplated rings; for most plated rings the maximum thickness will not exceed the minimum groove
width (W) minus 0.0002 inch.
Groove Maximum Bottom Radii: For shaft sizes 0.250 and smaller, 0.005 inch; for sizes 0.312
through 0.438, 0.010 inch; for sizes 0.500 and 0.562, 0.015 inch. Ring Free Diameter Tolerances:
For shaft sizes 0.094 through 0.156, +0.001, −0.003; for sizes 0.188 through 0.312, ±0.003; for sizes
0.375 through 0.562, ±0.004. Ring Thickness Tolerances: For all shaft sizes, ±0.002. Groove Diameter Tolerances: For shaft sizes 0.094 through 0.188, +0.002, −0.000; for sizes 0.219 and 0.250,
±0.002; for sizes 0.312 through 0.562, ±0.003. Groove Width Tolerances: For shaft sizes 0.094 and
0.125, +0.002, − 0.000; for sizes 0.156 through 0.562, +0.003, −0.000.
The thrust load capacities shown in the tables of this section include safety factors. Usually, a safety factor of 2 is used for groove thrust load calculations when the load is applied
through a retained part and groove with both having sharp corners and where the minimum
side clearance exists between the retained part and the shaft or bore. Groove thrust load
values in the tables of this section are based on these conditions. A safety factor of 3 is usual
for calculations of thrust load capacity based on ring shear.
Ideally, the corner of a retained part in contact with a retaining ring should have square
corners and contact the ring as closely as possible to the shaft or housing. The tabulated
thrust capacities assume that minimum clearances exist between the retained part and shaft
or housing, that the groove and retained part have square corners, and that contact between
the retained part and the ring occurs close to the shaft or housing. If these conditions apply,
the tabulated thrust loads apply. If the application does not meet the previous conditions
but the side clearances, radii, and chamfers are less than the maximum total radius or
chamfer of Fig. 1, then the thrust load capacity must be reduced by dividing the tabulated
value by 2. The maximum total radius is given by 0.5(b − d) and the maximum total chamfer by 0.375(b − d), where b is the radial wall thickness, and d is the groove depth. The recommended maximum total radius or chamfer specifications are intended to be used as
guidelines by the designer, and to ensure the ring application will withstand published and
calculated values of static thrust loads.
RETAINING RINGS
1707
In analyzing the retaining ring loading conditions, a static, uniformly applied load is usually assumed. Dynamic and eccentric loads, however, are frequently encountered. Eccentric loading occurs when the load is concentrated on a small portion of the ring, such as may
be caused by incorrectly machined surfaces, cocking of the retained part, and axial misalignment of parts. Conditions leading to eccentric loading on the ring should be avoided.
In addition to the factors that affect the static thrust capacity, applications in which shock
or impact loading occurs must be evaluated very carefully and tested in service to assess
the effect of the mass and velocity of the retained part striking the ring. Vibration caused by
impact loading can also cause the ring to fail if the resonant frequency of the system
(retaining ring application) coincides with the resonant frequency of the retaining ring.
;;;;;
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Table 16. Dimensions of Inch Series Self-Locking External Retaining Rings
A
T
L
S
U
H
Shaft Diameter
Min.
D
0.078
0.092
0.123
0.134
0.154
0.185
0.248
0.310
0.373
0.434
0.497
0.622
0.745
Max.
D
0.080
0.096
0.127
0.138
0.158
0.189
0.252
0.316
0.379
0.440
0.503
0.628
0.755
Ring
Free Dia.
A
0.074
0.089
0.120
0.130
0.150
0.181
0.238
0.298
0.354
0.412
0.470
0.593
0.706
Thickness
T
0.025
0.025
0.025
0.025
0.025
0.035
0.035
0.042
0.042
0.050
0.050
0.062
0.062
D
;;;
;;;
;;;
;;;
;;;
Optical Groove
Diameter
G
Width
W
0.041
0.048
0.048
0.056
0.056
0.069
0.069
GD
E
aStatic
Margin
E
The use of grooves with
these shaft sizes is not
suggested.
0.240
0.303
0.361
0.419
0.478
0.599
0.718
W
0.030
0.030
0.030
0.030
0.040
0.045
0.050
Thrust
Load (lb)
Ring
10
10
20
20
22
25
35
50
55
60
65
85
90
Groove
0
0
0
0
0
0
90
110
185
280
390
570
845
a Thrust Load Safety Factors: Ring, 1; groove, 2.
unplated rings; for plated, phosphate coated, and stainless steel rings, the maximum ring thickness
may be exceeded by 0.002 inch.
through 0.755, +0.004, −0.006. Ring Thickness Tolerances: For shaft sizes 0.078 through 0.158,
±0.002; for sizes 0.185 through 0.503, ±0.003; for sizes 0.622 through 0.755, ±0.004. Groove Diameter Tolerances: For shaft sizes less than 0.248, grooves are not recommended; for other sizes,
grooves are optional. For shaft sizes 0.248 through 0.316, +0.005, −0.0015; for sizes 0.373 through
0.628, +0.001, −0.002; for sizes 0.745 and 0.755, +0.002, −0.003. Groove Width Tolerances: For
shaft sizes 0.248 through 0.379, +0.003, −0.000; for sizes 0.434 through 0.755, +0.004, −0.000.
1708
RETAINING RINGS
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;
;
Table 17. Inch Series Internal and External Self-Locking Retaining Rings
Internal
C
T
C
D
E
Housing
Ring Dimensions
Min.
D
Max.
D
Thick.
T
Dia.
D
Margin
E
Static
Thrust
Load
0.311
0.374
0.437
0.498
0.560
0.623
0.748
0.873
0.936
0.998
1.248
1.436
1.498
0.313
0.376
0.439
0.502
0.564
0.627
0.752
0.877
0.940
1.002
1.252
1.440
1.502
0.010
0.010
0.010
0.010
0.010
0.010
0.015
0.015
0.015
0.015
0.015
0.015
0.015
0.136
0.175
0.237
0.258
0.312
0.390
0.500
0.625
0.687
0.750
0.938
1.117
1.188
0.040
0.040
0.040
0.040
0.040
0.040
0.060
0.060
0.060
0.060
0.060
0.060
0.060
80
75
70
60
50
45
75
70
70
70
60
60
60
External
T
D
E
Shaft
Ring Dimensions
Min.
D
Max.
D
Thick.
T
Dia.
D
Margin
E
Static
Thrust
Load
0.093
0.124
0.155
0.187
0.218
0.239
0.249
0.311
0.374
0.437
0.498
0.560
0.623
0.748
0.873
0.998
0.095
0.126
0.157
0.189
0.220
0.241
0.251
0.313
0.376
0.440
0.502
0.564
0.627
0.752
0.877
1.002
0.010
0.010
0.010
0.010
0.010
0.015
0.010
0.010
0.010
0.015
0.015
0.015
0.015
0.015
0.015
0.015
0.250
0.325
0.356
0.387
0.418
0.460
0.450
0.512
0.575
0.638
0.750
0.812
0.875
1.000
1.125
1.250
0.040
0.040
0.040
0.040
0.040
0.060
0.040
0.040
0.040
0.060
0.060
0.060
0.060
0.060
0.060
0.060
15
20
25
35
35
35
40
40
40
50
50
50
50
50
55
60
Source: Industrial Retaining Rings, 6000 Series (internal) and 6100 Series (external). All dimensions are in inches, thrust loads are in pounds. Thickness indicated is for unplated rings. Standard
material: carbon spring steel (SAE 1060-1090).
Internal Rings: Thrust loads are for rings made of standard material inserted into cold-rolled, lowcarbon housing. Ring Thickness Tolerances: For housing sizes 0.311 through 0.627, ±0.001; for
sizes 0.748 through 1.502, ±0.002. Ring Diameter Tolerances: For housing sizes 0.311 through
External Rings: Thrust loads are for rings made of standard material installed onto cold-rolled,
low-carbon shafts. Ring Thickness Tolerances: For shaft sizes 0.093 through 0.220, ±0.001; for size
0.239, ±0.002; for sizes 0.249 through 0.376, ±0.001; for sizes 0.437 through 1.002, ±0.002. Ring
Diameter Tolerances: For shaft sizes 0.093 through 0.502, ±0.005; for sizes 0.560 through 1.002,
±0.010.
Centrifugal Capacity: Proper functioning of a retaining ring depends on the ring remaining seated on the groove bottom. External rings “cling” to the groove bottom because the
ring ID is slightly smaller than the diameter at the bottom of the groove. Ring speed should
be kept below the allowable steady-state speed of the ring, or self-locking rings specially
designed for high-speed applications should be used, otherwise an external ring can lose its
grip on the groove. Applications of large retaining rings that tend to spin in their grooves
when subjected to sudden acceleration or deceleration of the retained part can benefit from
a ring with more “cling” (i.e., a smaller interior diameter) as long as the stress of installation is within permissible limits. Special rings are also available that lock into a hole in the
bottom of the groove, thereby preventing rotation. The following equation can be used to
determine the allowable steady-state speed N of an external spiral retaining ring:
RETAINING RINGS
N =
1709
0.466C 1 E 3 × 10 12
--------------------------------------------------R n3 ( 1 + C 1 ) ( R o3 – R i3 )
(1)
where the speed N is in revolutions per minute, C1 is the minimum ring cling to groove bottom, E is the ring radial wall, Rn is the free neutral ring radius, Ro is the free outside ring
radius, and Ri is the free inside ring radius, all in inches. For external spiral rings, the minimum ring cling is given by: C1 = (C − G)/G, where C is the mean groove diameter in inches,
and G is the maximum ring free ID in inches.
;
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;
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;
;
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;;
;
;
;;
;;
;
;
;;
;;
;
;
;;
;;
;;
;;
;;
(a)
(b)
(c)
Fig. 2. Localized Groove Yielding under Load. (a) Groove Profile before Loading;
(b) Localized Yielding of Retained Part and Groove under Load; (c) Groove Profile
after Loading beyond Thrust Capacity (Courtesy Spirolox Retaining Rings)
Rotation between Parts: The use of spiral-wound rings to retain a rotating part should be
limited to applications with rotation in only one direction. The ring should be matched so
that the rotation tends to wind the spring into the groove. External rings should be wound
in the direction of rotation of the retained part but internal rings should be wound against
the direction of rotation of the rotating part. Failure to observe these precautions will cause
the ring to wind out of the groove. Spiral-wound rings can be obtained with either righthand (normal rotation) or left-hand (reverse rotation) wound configurations. Stamped
retaining rings do not have these limitations, and may be used for applications that require
rotation of the retained part, regardless of the direction of rotation.
Retaining Ring Failure.—Failure of a retaining ring application can result from failure
of the ring itself, failure of the groove, or both. If a ring fails, the cause is likely to be from
shearing of the ring. Shear failure occurs when a ring is installed in a groove and loaded by
a retained part with both the groove and the retained part having a compressive yield
strength greater than 45,000 psi; or when the load is applied through a retained part and
groove, both having sharp corners and line-to-line contact; or when the ring is too thin in
section compared with its diameter. To examine the possibility of ring shear, the allowable
thrust Ps, based on the shear strength of the ring material, is given by
πDtS
P s = ---------------s
(2)
K
where Ps is in lbf, D is the shaft or housing diameter in inches, t is the ring thickness in
inches, Ss is the shear strength of the ring material in lb/in.2, and K is the factor of safety.
Groove Failure: The most common type of groove failure is yielding of the groove material that occurs when the thrust load, applied through the retaining ring against the corner
of the groove, exceeds the compressive yield strength of the groove. This yielding of the
groove results from a low compressive yield strength of the groove material, and allows the
ring to tilt and come out of the groove, as illustrated in Fig. 2(b).
When dishing of a ring occurs as a result of yielding in the groove material, a bending
moment across the cross-section of the ring generates a tensile stress that is highest at the
1710
RETAINING RINGS
interior diameter of the ring. If the maximum stress is greater than the yield strength of the
ring material, the ring ID will grow and the ring will become permanently dished in shape.
To determine the thrust load capacity of a ring based on groove deformation, the allowable
angle of ring deflection must be calculated, then the thrust load based on groove yield can
be determined. However, for spiral-wound rings, the thrust load PG that initiates the onset
of groove deformation can be estimated from the following:
πDdS
P G = ----------------yK
(3)
where PG is given in lbf, D is the shaft or housing diameter in inches, d is the groove depth
in inches, Sy is the yield strength of the groove material, and K is the safety factor. For
stamped rings, estimate PG by multiplying Equation (3) by the fraction of the groove circumference that contacts the ring.
The thrust load capacity of a particular retaining ring application can be increased by
changing the workpiece material that houses the groove. Increasing the yield strength of
the groove material increases the thrust load capacity of the retaining ring application.
However, increasing the strength of the groove material may cause the failure mechanism
to shift from groove deformation to ring shear. Therefore, use the lower of the values
obtained from Equations (2) and (3) for the allowable thrust load.
Groove Design and Machining: In most applications, grooves are located near the end of
a shaft or housing bore to facilitate installation and removal of the rings. The groove is normally located a distance at least two to three times the groove depth from the end of the
shaft or bore. If the groove is too close to the end of the shaft or bore, the groove may shear
or yield. The following equation can be used to determine the minimum safe distance Y of
a groove from the end of a shaft or housing:
KP t
Y = ------------πDS c
(4)
where K is the factor of safety, Pt is the thrust load on the groove in pounds, Sc is the shear
strength of the groove material in psi, and D is the shaft or housing diameter in inches.
A properly designed and machined groove is just as important in a retaining ring application as the ring itself. The walls of grooves should be perpendicular to the shaft or bore
diameter; the grooves should have square corners on the top edges, and radii at the bottom,
within the tolerances specified by the manufacturers, as shown in Fig. 1 (page 1684). Test
data indicate that the ultimate thrust capacity for both static and dynamic loading conditions is greatly affected if these groove requirements are not met. For spiral-wound rings,
the maximum bottom groove radius is 0.005 inch for rings up to 1.000 inch free diameter
and 0.010 inch for larger rings, internal or external. For stamped rings, the maximum bottom groove radius varies with ring size and style.
Table 18. Retaining Ring Standards
MIL-R-21248B
Military
MS-16633 Open-type external uniform cross-section
MS-16634 Open-type external uniform cross-section
cylindrically
MS-3215 Open-type external tapered cross-section
MS-16632 Crescent-type external
MS-16625 Internal
MS-16629 Internal cylindrically bowed
MS-16624 Closed-type external tapered cross-section
RETAINING RINGS
1711
Table 18. Retaining Ring Standards (Continued)
Military
MS-16628 Closed-type external tapered cross-section cylindrically
bowed
MIL-R-21248B
MS-16627 Internal inverted
MS-16626 Closed-type external tapered cross-section
MS-90707 Self-locking external tapered cross-section
MIL-R-27426
AS 3215
AS 3216
AS 3217
AS 3218
AS 3219
B27.6-1972, R1983
B27.7-1977, R1983
B27.8M-1977, R1983
MA4016
MA4017
MA4020
MA4021
MA4029
MA4030
MA4035
MA4036
DIN 471, 472, 6799,
984, 5417, 7993
LN 471, 472, 6799
MS-3217 External heavy-duty tapered cross-section
Uniform cross-section spiral retaining rings, Type
1-External, Type 2-Internal
Acrospace Standard
Ring, Retaining—Spiral, Internal, Heavy Duty, Stainless Steel
Ring, Retaining—Spiral, External, Heavy Duty, Stainless Steel
Ring, Retaining—Spiral, Internal, Light Duty, Stainless Steel
Ring, Retaining—Spiral, External, Light Duty, Stainless Steel
Ring, Wound, Dimensional and Acceptance Standard for
Spiral Wound Retaining Rings
ANSI
General Purpose Uniform Cross-Section Spiral Retaining Rings
General Purpose Tapered and Reduced Cross-Section
Retaining Rings (Metric)
General Purpose Metric Tapered and Reduced CrossSection Retaining Rings
Type 3DM1—Heavy Duty External Rings
Type 3EM1—Reinforced “E” Rings
Type 3FM1—“C” Type Rings
ANSI/SAE
Ring, Retaining—External Spiral Wound, Heavy and
Medium Duty, Crescent, Metric
Ring, Retaining—External Spiral Wound, Heavy and
Medium Duty, Crescent, Metric
Ring, Retaining—External Tapered, Type 1, Class 2,
AMS 5520, Metric
Ring, Retaining—Internal Tapered, Type 1, Class 1, AMS
5520, Metric
Ring, Retaining—Internal, Beveled, Tapered, Type 2,
Class 1, AMS 5520, Metric
Ring, Retaining—External, Reinforced E-Ring, Type 1,
Class 3, AMS 5520, Metric
Rings, Retaining—Spiral Wound, Uniform Section,
Corrosion Resistant, Procurement Specification for, Metric
Ring, Retaining—Tapered Width, Uniform Thickness,
Corrosion Resistant, Procurement Specification for, Metric
DIN
Standards for normal and heavy type, internal and external
retaining rings and retaining washers
Aerospace standards for internal and external retaining rings
1712
WING NUTS, WING SCREWS AND THUMB SCREWS
WING NUTS, WING SCREWS, AND THUMB SCREWS
Wing Nuts.—A wing nut is a nut having wings designed for manual turning without
driver or wrench. As covered by ANSI B18.17-1968 (R1983) wing nuts are classified first,
by type on the basis of the method of manufacture; and second, by style on the basis of
design characteristics. They consist of:
Type A: Type A wing nuts are cold forged or cold formed solid nuts having wings of
moderate height. In some sizes they are produced in regular, light, and heavy series to best
suit the requirements of specific applications. Dimensions are given in Table 1.
Table 1. American National Standard Type A Wing Nuts
ANSI B18.17-1968, R1983
Nominal
Size or
Basic Major
Diameter
of Threada
Thds.
per
Inch
3
4
(0.0990)
(0.1120)
48, 56
40, 38
5
(0.1250)
40, 44
6
(0.1380)
32, 40
8
(0.1640)
32, 36
10
(0.1900)
24, 32
12
(0.2160)
24, 28
1⁄
4
(0.2500)
20, 28
5⁄
16
(0.3125)
18, 24
Seriesb
Nut
Blank
Size
(Ref)
AA
AA
AA
A
AA
A
A
B
A
B
B
C
B
C
D
C
D
E
D
E
E
F
E
F
F
A
B
C
D
E
G
Wing
Spread
Wing
Height
Wing
Thick.
Between
Wings
Boss
Dia.
Boss
Height
Max Min Max Min Max Min Max Min Max Min Max Min
3⁄
8
(0.3750)
16, 24
7⁄
16
(0.4375)
14, 20
1⁄
2
(0.5000)
13, 20
9⁄
16
5⁄
8
3⁄
4
(0.5625)
12, 18
Hvy.
Hvy.
Lgt.
Hvy.
Lgt.
Hvy.
Lgt.
Hvy.
Lgt.
Hvy.
Lgt.
Hvy.
Lgt.
Reg.
Hvy.
Lgt.
Reg.
Hvy.
Lgt.
Reg.
Lgt.
Hvy.
Lgt.
Hvy.
Hvy.
0.72
0.72
0.72
0.91
0.72
0.91
0.91
1.10
0.91
1.10
1.10
1.25
1.10
1.25
1.44
1.25
1.44
1.94
1.44
1.94
1.94
2.76
1.94
2.76
2.76
0.59
0.59
0.59
0.78
0.59
0.78
0.78
0.97
0.78
0.97
0.97
1.12
0.97
1.12
1.31
1.12
1.31
1.81
1.31
1.81
1.81
2.62
1.81
2.62
2.62
0.41
0.41
0.41
0.47
0.41
0.47
0.47
0.57
0.47
0.57
0.57
0.66
0.57
0.66
0.79
0.66
0.79
1.00
0.79
1.00
1.00
1.44
1.00
1.44
1.44
0.28
0.28
0.28
0.34
0.28
0.34
0.34
0.43
0.34
0.43
0.43
0.53
0.43
0.53
0.65
0.53
0.65
0.87
0.65
0.87
0.87
1.31
0.87
1.31
1.31
0.11
0.11
0.11
0.14
0.11
0.14
0.14
0.18
0.14
0.18
0.18
0.21
0.18
0.21
0.24
0.21
0.24
0.33
0.24
0.33
0.33
0.40
0.33
0.40
0.40
0.07
0.07
0.07
0.10
0.07
0.10
0.10
0.14
0.10
0.14
0.14
0.17
0.14
0.17
0.20
0.17
0.20
0.26
0.20
0.26
0.26
0.34
0.26
0.34
0.34
0.21
0.21
0.21
0.27
0.21
0.27
0.27
0.33
0.27
0.33
0.33
0.39
0.39
0.39
0.48
0.39
0.48
0.65
0.48
0.65
0.65
0.90
0.65
0.90
0.90
0.17
0.17
0.17
0.22
0.17
0.22
0.22
0.26
0.22
0.26
0.26
0.32
0.26
0.32
0.42
0.32
0.42
0.54
0.42
0.54
0.54
0.80
0.54
0.80
0.80
0.33
0.33
0.33
0.43
0.33
0.43
0.43
0.50
0.43
0.50
0.50
0.58
0.50
0.58
0.70
0.58
0.70
0.93
0.70
0.93
0.93
1.19
0.93
1.19
1.19
0.29
0.29
0.29
0.39
0.29
0.39
0.39
0.45
0.39
0.45
0.45
0.51
0.45
0.51
0.64
0.51
0.64
0.86
0.64
0.86
0.86
1.13
0.86
1.13
1.13
0.14
0.14
0.14
0.18
0.14
0.18
0.18
0.22
0.18
0.22
0.22
0.25
0.22
0.25
0.30
0.25
0.30
0.39
0.30
0.39
0.39
0.55
0.39
0.55
0.55
(0.6250)
11, 18
Hvy.
F
2.76 2.62 1.44 1.31 0.40 0.34 0.90 0.80 1.19 1.13 0.55 0.51
(0.7500)
10, 16
Hvy.
F
2.76 2.62 1.44 1.31 0.40 0.34 0.90 0.80 1.19 1.13 0.55 0.51
a Where specifying nominal size in decimals, zeros in the fourth decimal place are omitted.
b Lgt. = Light; Hvy. = Heavy; Reg. = Regular. Sizes shown in bold face are preferred.
0.10
0.10
0.10
0.14
0.10
0.14
0.14
0.17
0.14
0.17
0.17
0.20
0.17
0.20
0.26
0.20
0.26
0.35
0.26
0.35
0.35
0.51
0.35
0.51
0.51
1713
Type B: Type B wing nuts are hot forged solid nuts available in two wing styles: Style 1,
having wings of moderate height; and Style 2, having high wings. Dimensions are given in
Table 2.
Table 2. American National Standard Type B Wing Nuts
ANSI B18.17-1968, R1983
STYLE 1
Nominal
Size or
Basic Major
Diameter
of Threada
Thds.
per
Inch
STYLE 2
A
B
C
D
E
G
Wing
Spread
Wing
Height
Wing
Thick.
Between
Wings
Boss
Dia.
Boss
Height
Max
Min
Max
Min
Max
Min
Max
Min
Max
Min
Max
Min
Type B, Style 1
5 (0.1250)
40
0.78
0.72
0.36
0.30
0.13
0.10
0.28
0.22
0.31
0.28
0.22
0.16
10 (0.1900)
24
0.97
0.91
0.45
0.39
0.15
0.12
0.34
0.28
0.39
0.36
0.28
0.22
0.28
1⁄ (0.2500)
4
20
1.16
1.09
0.56
0.50
0.17
0.14
0.41
0.34
0.47
0.44
0.34
5⁄ (0.3125)
16
18
1.44
1.38
0.67
0.61
0.18
0.15
0.50
0.44
0.55
0.52
0.41
0.34
3⁄ (0.3750)
8
16
1.72
1.66
0.80
0.73
0.20
0.17
0.59
0.53
0.63
0.60
0.47
0.41
7⁄ (0.4375)
16
14
2.00
1.94
0.91
0.84
0.21
0.18
0.69
0.62
0.71
0.68
0.53
0.47
1⁄ (0.5000)
2
13
2.31
2.22
1.06
0.94
0.23
0.20
0.78
0.69
0.79
0.76
0.62
0.50
9⁄ (0.5625)
16
12
2.59
2.47
1.17
1.05
0.25
0.21
0.88
0.78
0.88
0.84
0.69
0.56
5⁄ (0.6250)
8
11
2.84
2.72
1.31
1.19
0.27
0.23
0.94
0.84
0.96
0.92
0.75
0.62
3⁄ (0.7500)
4
10
3.31
3.19
1.52
1.39
0.29
0.25
1.10
1.00
1.12
1.08
0.88
0.75
Type B, Style 2
5 (0.1250)
40
0.81
0.75
0.62
0.56
0.12
0.09
0.28
0.22
0.31
0.28
0.22
0.16
10 (0.1900)
24
1.01
0.95
0.78
0.72
0.14
0.11
0.35
0.29
0.39
0.36
0.28
0.22
0.28
1⁄ (0.2500)
4
20
1.22
1.16
0.94
0.88
0.16
0.13
0.41
0.35
0.47
0.44
0.34
5⁄ (0.3125)
16
18
1.43
1.37
1.09
1.03
0.17
0.14
0.48
0.42
0.55
0.52
0.41
0.34
3⁄ (0.3750)
8
16
1.63
1.57
1.25
1.19
0.18
0.15
0.55
0.49
0.63
0.60
0.47
0.41
7⁄ (0.4375)
16
14
1.90
1.84
1.42.
1.36
0.19
0.16
0.62
0.56
0.71
0.68
0.53
0.47
1⁄ (0.5000)
2
13
2.13
2.04
1.58
1.45
0.20
0.17
0.69
0.60
0.79
0.76
0.62
0.50
9⁄ (0.5625)
16
12
2.40
2.28
1.75
1.62
0.22
0.18
0.76
0.67
0.88
0.84
0.69
0.56
5⁄ (0.6250)
8
11
2.60
2.48
1.91
1.78
0.23
0.19
0.83
0.74
0.96
0.92
0.75
0.62
3⁄ (0.7500)
4
10
3.02
2.90
2.22
2.09
0.24
0.20
0.97
0.88
1.12
1.08
0.88
0.75
1714
Table 3. American National Standard Type C Wing Nuts ANSI B18.17-1968, R1983
STYLE 1
Nominal
Size or
Basic Major
Diameter
of Threada
Thds.
per
Inch
4 (0.1120)
5 (0.1250)
40
40
6 (0.1380)
32
Serie
s
STYLE 2
STYLE 3
A
B
C
D
E
F
G
Nut
Blan
Wing
Wing
Wing
Between
Boss
Boss
Boss
k
Spread
Height
Thick.
Wings
Dia.
Dia.
Height
Size
(Ref) Max Min Max Min Max Min Max Min Max Min Max Min Max Min
Type C, Style 1
8 (0.1640)
32
10 (0.1900) 24, 32
Reg.
Reg.
Reg.
Hvy.
Reg.
Reg.
Reg.
Hvy.
AA
AA
AA
A
A
A
A
B
0.66
0.66
0.66
0.85
0.85
0.85
0.85
1.08
0.64
0.64
0.64
0.83
0.83
0.83
0.83
1.05
0.36
0.36
0.36
0.43
0.43
0.43
0.43
0.57
0.35
0.35
0.35
0.42
0.42
0.42
0.42
0.53
0.11
0.11
0.11
0.14
0.14
0.14
0.14
0.16
0.09
0.09
0.09
0.12
0.12
0.12
0.12
0.14
0.18
0.18
0.18
0.29
0.29
0.29
0.29
0.32
0.16
0.16
0.16
0.27
0.27
0.27
0.27
0.30
0.27
0.27
0.27
0.38
0.38
0.38
0.38
0.44
0.25
0.25
0.25
0.36
0.36
0.36
0.36
0.42
0.32
0.32
0.32
0.41
0.41
0.41
0.41
0.48
0.30
0.30
0.30
0.40
0.40
0.40
0.40
0.46
0.16
0.16
0.16
0.20
0.20
0.20
0.20
0.23
0.14
0.14
0.14
0.18
0.18
0.18
0.18
0.21
12 (0.2160)
24
1⁄ (0.2500)
4
20, 28
Reg.
B
5⁄ (0.3125)
16
18, 24
Reg.
C
1.23 1.20 0.64 0.62 0.20 0.18 0.39 0.35 0.50 0.49 0.57 0.55 0.26 0.24
3⁄ (0.3750)
8
16, 24
Reg.
D
1.45 1.42 0.74 0.72 0.23 0.21 0.46 0.42 0.62 0.60 0.69 0.67 0.29 0.27
7⁄ (0.4375)
16
14, 20
1⁄ (0.5000)
2
13, 20
Reg.
Hvy.
Reg.
Hvy.
E
EH
E
EH
1.89
1.89
1.89
1.89
1.86
1.86
1.86
1.86
…
…
…
…
…
…
…
…
…
…
0.82
0.82
1.01
1.01
1.20
0.80
0.80
0.99
0.99
1.18
5 (0.1250)
40
6 (0.1380)
32
8 (0.1640)
32
10 (0.1900) 24, 32
12 (0.2160)
24
1.08 1.05 0.57 0.53 0.16 0.14 0.32 0.30 0.44 0.42 0.48 0.46 0.23 0.21
0.91
0.93
0.91
0.93
0.90 0.29 0.28
0.91 0.34 0.33
0.90 0.29 0.28
0.91 0.34 0.33
Type C, Style 2
0.25 0.23 0.09 0.08
0.25 0.23 0.09 0.08
0.28 0.27 0.11 0.09
0.28 0.27 0.11 0.09
0.32 0.31 0.12 0.11
0.67
0.63
0.67
0.63
0.65
0.62
0.65
0.62
0.75
0.81
0.75
0.81
0.73
0.79
0.73
0.79
0.83
0.89
0.83
0.89
0.82
0.87
0.82
0.87
0.38
0.42
0.38
0.42
0.37
0.40
0.37
0.40
0.21
0.21
0.29
0.29
0.38
0.19
0.19
0.28
0.28
0.37
0.26
0.26
0.36
0.36
0.44
0.24
0.24
0.34
0.34
0.43
…
…
…
…
…
…
…
…
…
…
0.17
0.17
0.19
0.19
0.22
0.15
0.15
0.18
0.18
0.20
1⁄ (0.2500)
4
20
…
…
1.20 1.18 0.32 0.31 0.12 0.11 0.38 0.37 0.44 0.43
…
…
0.22 0.20
5⁄ (0.3125)
16
18
…
…
1.51 1.49 0.36 0.35 0.14 0.12 0.44 0.43 0.51 0.49
…
…
0.24 0.23
3⁄ (0.3750)
8
16
5 (0.1250)
40
6 (0.1380)
32
8 (0.1640)
32
10 (0.1900) 24, 32
12 (0.2160)
24
…
…
1.89 1.86 0.58 0.55 0.20 0.17 0.44 0.43 0.63 0.62
…
…
…
…
…
…
…
…
…
…
0.92
0.92
0.92
1.14
1.14
0.89
0.89
0.89
1.12
1.12
0.70
0.70
0.70
0.85
0.85
Type C, Style 3
0.67 0.16 0.15
0.67 0.16 0.15
0.67 0.16 0.15
0.83 0.19 0.17
0.83 0.19 0.17
0.26
0.26
0.26
0.32
0.32
0.24
0.24
0.24
0.30
0.30
0.38
0.38
0.38
0.44
0.44
0.36
0.36
0.36
0.42
0.42
…
…
0.37 0.35
…
…
…
…
…
…
…
…
…
…
0.25
0.25
0.25
0.29
0.29
0.24
0.24
0.24
0.27
0.27
1⁄ (0.2500)
4
20
…
…
1.14 1.12 0.85 0.83 0.19 0.17 0.32 0.30 0.44 0.42
…
…
0.29 0.27
5⁄ (0.3125)
16
18
…
…
1.29 1.27 1.04 1.02 0.23 0.22 0.39 0.36 0.50 0.49
…
…
0.35 0.34
3⁄ (0.3750)
8
16
…
…
1.51 1.49 1.20 1.18 0.27 0.25 0.45 0.42 0.62 0.60
…
…
0.43 0.42
All dimensions in inches. Sizes shown in bold face are preferred.
Type C: Type C wing nuts are die cast solid nuts and are available in three wing styles:
Style 1, having wings of moderate height; Style 2, having low wings; and Style 3, having
high wings. In some sizes, the Style 1 nuts are produced in regular, light, and heavy series
to best suit the requirements of specific applications. Dimensions are given in Table 3.
1715
Table 4. American National Standard Type D Wing Nuts ANSI B18.17-1968, R1983
STYLE 1
STYLE 2 (LOW WING)
Nominal
Size or
Basic Major
Diameter
of Threada
Thds.
per
Inch
Seriesb
8 (0.1640)
10 (0.1900)
12 (0.2160)
1⁄ (0.2500)
4
32, 36
24, 32
24, 28
20, 28
…
…
…
…
5⁄ (0.3125)
16
3⁄ (0.3750)
8
18, 24
16, 24
5 (0.1250)
6 (0.1380)
8 (0.1640)
40
32
32
10 (0.1900)
24, 32
12 (0.2160)
1⁄ (0.2500)
4
24
20
10 (0.1900)
24, 32
12 (0.2160)
24
1⁄ (0.2500)
4
20
5⁄ (0.3125)
16
18
A
Wing
Spread
E
Boss
Dia.
Max Min Max Min Max Min
Type D, Style 1
Min
Max Min
0.78
0.91
1.09
1.11
0.14
0.17
0.17
0.21
0.25
0.34
0.34
0.34
0.41
0.53
0.53
0.62
0.35
0.47
0.47
0.56
…
1.30 1.24 0.59 0.53 0.30 0.26
0.46
0.73 0.67
…
1.41 1.34 0.67 0.61 0.34 0.30
0.69
0.83 0.77
0.30
0.30
0.30
0.32
0.60
0.60
0.60
0.40
0.40
0.40
0.53
0.61
0.61
0.61
0.47
0.50
0.59
0.59
0.70
0.66
0.70
0.66
0.65
0.75
0.73
0.73
1.03
1.03
1.03
1.03
0.40
0.47
0.47
0.50
0.34
0.41
0.41
0.44
C
Wing
Thick.
STYLE 3 (LARGE BASE)
D
Between
Wings
0.72
0.85
1.03
1.05
B
Wing
Height
0.18
0.21
0.21
0.25
Reg.
Reg.
Reg.
Reg.
Hvy.
Reg.
Reg.
1.03
1.03
1.03
1.40
1.21
1.21
1.21
0.97
0.97
0.97
1.34
1.16
1.16
1.16
Type D, Style 2
0.25 0.19 0.19 0.13
0.25 0.19 0.19 0.13
0.25 0.19 0.19 0.13
0.34 0.28 0.25 0.18
0.28 0.26 0.31 0.25
0.28 0.26 0.31 0.25
0.28 0.26 0.31 0.25
Lgt.
Reg.
Reg.
Lgt.
Reg.
Hvy.
Reg.
Hvy.
1.31
1.40
1.28
1.28
1.78
1.47
1.78
1.47
1.25
1.34
1.22
1.22
1.72
1.40
1.72
1.40
Type D, Style 3
0.48 0.42 0.29 0.23
0.53 0.47 0.25 0.19
0.40 0.34 0.23 0.17
0.40 0.34 0.23 0.17
0.66 0.60 0.31 0.25
0.50 0.44 0.37 0.31
0.66 0.60 0.31 0.25
0.50 0.44 0.37 0.31
G
Boss
Hgt.
H
Wall
Hgt.
T
Stock
Thick.
Min
Min
Max Min
0.08
0.10
0.10
0.11
0.12
0.12
0.12
0.12
0.04
0.04
0.05
0.05
0.14
0.18
0.06 0.05
0.16
0.18
0.06 0.05
0.34
0.34
0.34
0.47
0.55
0.55
0.55
0.07
0.08
0.08
0.09
0.09
0.11
0.11
0.09
0.09
0.09
0.16
0.13
0.13
0.13
0.04
0.04
0.04
0.05
0.05
0.05
0.05
0.03
0.03
0.03
0.04
0.04
0.04
0.04
0.59
0.69
0.67
0.67
0.97
0.97
0.97
0.97
0.08
0.08
0.11
0.11
0.14
0.14
0.14
0.14
0.12
0.14
0.12
0.12
0.17
0.14
0.17
0.14
0.04
0.04
0.04
0.04
0.06
0.08
0.06
0.08
0.03
0.03
0.03
0.03
0.04
0.06
0.04
0.06
0.03
0.03
0.04
0.04
b Lgt. = Light; Hvy. = Heavy; Reg. = Regular.
Type D: Type D wing nuts are stamped sheet metal nuts and are available in three styles:
Style 1, having wings of moderate height; Style 2, having low wings; and Style 3, having
wings of moderate height and a larger bearing surface. In some sizes, Styles 2 and 3 are
produced in regular, light, and heavy series to best suit the requirements of specific applications. Dimensions are given in Table 4.
Specification of Wing Nuts.—When specifying wing nuts, the following data should be
included in the designation and should appear in the following sequence: nominal size
(number, fraction or decimal equivalent), threads per inch, type, style and/or series, material, and finish.
Examples: 10—32 Type A Wing Nut, Regular Series, Steel, Zinc Plated.
0.250—20 Type C Wing Nut, Style 1, Zinc Alloy, Plain.
Threads for Wing Nuts.—Threads are in conformance with the ANSI Standard Unified
Thread, Class 2B for all types of wing nuts except type D which have a modified Class 2B
thread. Because of the method of manufacture, the minor diameter of the thread in type D
1716
nuts may be somewhat larger than the Unified Thread Class 2B maximum but shall in no
case exceed the minimum pitch diameter.
Materials and Finish for Wing Nuts.—Types A, B, and D wing nuts are normally supplied as specified by the user in carbon steel, brass or corrosion resistant steel of good quality and adaptable to the manufacturing process. Type C wing nuts are made from die cast
zinc alloy. Unless otherwise specified, wing nuts are supplied with a plain (unplated or
uncoated) finish.
Wing Screws.—A wing screw is a screw having a wing-shaped head designed for manual
turning without a driver or wrench. As covered by ANSI B18.17-1968 (R1983) wing
screws are classified first, by type on the basis of the method of manufacture, and second,
by style on the basis of design characteristics. They consist of the following:
Type A: Type A wing screws are of two-piece construction having cold formed or cold
forged wing portions of moderate height. In some sizes they are produced in regular, light,
and heavy series to best suit the requirements of specific applications. Dimensions are
given in Table 5.
Type B: Type B wing screws are of hot forged one-piece construction available in two
wing styles: Style 1, having wings of moderate height; and Style 2, having high wings.
Dimensions are given in Table 5.
Type C: Type C wing screws are available in two styles: Style 1, of a one-piece die cast
construction having wings of moderate height; and Style 2, of a two-piece construction
having a die cast wing portion of moderate height. Dimensions are given in Table 6.
Type D: Type D wing screws are of two-piece welded construction having stamped sheet
metal wing portions of moderate height. Dimensions are given in Table 6.
Materials for Wing Screws and Thumb Screws: Type A wing screws are normally supplied in carbon steel with the shank portion case hardened. When so specified, they also
may be made from corrosion resistant steel, brass or other materials as agreed upon by the
manufacturer and user.
Type B wing screws are normally made from carbon steel but also may be made from
corrosion resistant steel, brass or other materials.
Type C, Style 1, wing screws are supplied only in die cast zinc alloy. Type C, Style 2,
wing screws have the wing portion made from die cast zinc alloy with the shank portion
normally made from carbon steel. Where so specified, the shank portion may be made
from corrosion resistant steel, brass or other materials as agreed upon by the manufacturer
and user.
Type D wing screws are normally supplied in carbon steel but also may be made from
corrosion resistant steel, brass or other materials.
Thumb screws of all types are normally made from a good commercial quality of carbon
steel having a maximum ultimate tensile strength of 48,000 psi. Where so specified, carbon steel thumb screws are case hardened. They are also made from corrosion resistant
steel, brass, and other materials as agreed upon by the manufacturer and user.
Unless otherwise specified, wing screws and thumb screws are supplied with a plain
(unplated or uncoated) finish.
Thumb Screws.—A thumb screw is a screw having a flattened head designed for manual
turning without a driver or wrench. As covered by ANSI B18.17-1968 (R1983) thumb
screws are classified by type on the basis of design characteristics. They consist of the following:
Type A: Type A thumb screws are forged one-piece screws having a shoulder under the
head and are available in two series: regular and heavy. Dimensions are given in Table 7.
Type B: Type B thumb screws are forged one-piece screws without a shoulder and are
available in two series: regular and heavy. Dimensions are given in Table 7.
1717
Table 5. American National Standard Types A and B Wing Screws
ANSI B18.17-1968, R1983
TYPE A
Nominal
Size or
Basic
Major
Diametera
Thds.
per
Inch
Seriesb
TYPE B
Head
Blank
size
(Ref)
A
B
C
E
G
L
Wing
Spread
Wing
Height
Wing
Thick.
Boss
Dia.
Boss
Height.
Practical
Screw
Lengths
Max Min Max Min Max Min Max Min Max Min
Max
Min
Type A
4 (0.1120)
40
6 (0.1380)
32
8 (0.1640)
32
10 (0.1900)
12 (0.2160)
1⁄ (0.2500)
4
5⁄ (0.3125)
16
3⁄ (0.3750)
8
7⁄ (0.4375)
16
24, 32
24
20
18
16
14
1⁄ (0.5000)
2
13
5⁄ (0.6250)
8
11
Hvy.
AA
0.72 0.59 0.41 0.28 0.11 0.07 0.33 0.29 0.14 0.10
Lgt.
AA
0.72 0.59 0.41 0.28 0.11 0.07 0.33 0.29 0.14 0.10
Hvy.
A
0.91 0.78 0.47 0.34 0.14 0.10 0.43 0.39 0.18 0.14
Lgt.
A
0.91 0.78 0.47 0.34 0.14 0.10 0.43 0.39 0.18 0.14
Hvy.
B
1.10 0.97 0.57 0.43 0.18 0.14 0.50 0.45 0.22 0.17
Lgt.
A
0.91 0.78 0.47 0.34 0.14 0.10 0.43 0.39 0.18 0.14
Hvy.
B
1.10 0.97 0.57 0.43 0.18 0.14 0.50 0.45 0.22 0.17
Lgt.
B
1.10 0.97 0.57 0.43 0.18 0.14 0.50 0.45 0.22 0.17
0.75 0.25
} 0.75 0.25
} 0.75 0.38
} 1.00 0.38
} 1.00 0.38
Hvy.
C
1.25 1.12 0.66 0.53 0.21 0.17 0.58 0.51 0.25 0.20
Lgt.
B
1.10 0.97 0.57 0.43 0.18 0.14 0.50 0.45 0.22 0.17
C
1.25 1.12 0.66 0.53 0.21 0.17 0.58 0.51 0.25 0.20 } 1.50 0.50
Reg.
Hvy.
D
1.44 1.31 0.79 0.65 0.24 0.20 0.70 0.64 0.30 0.26
Lgt.
C
1.25 1.12 0.66 0.53 0.21 0.17 0.58 0.51 0.25 0.20
1.44 1.31 0.79 0.65 0.24 0.20 0.70 0.64 0.30 0.26 } 1.50 0.50
Reg.
D
Hvy.
E
1.94 1.81 1.00 0.87 0.33 0.26 0.93 0.86 0.39 0.35
Lgt.
D
1.44 1.31 0.79 0.65 0.24 0.20 0.70 0.64 0.30 0.26
1.94 1.81 1.00 0.87 0.33 0.26 0.93 0.86 0.39 0.35 } 2.00 0.75
Reg.
E
Hvy.
F
2.76 2.62 1.44 1.31 0.40 0.34 1.19 1.13 0.55 0.51
Lgt.
E
1.94 1.81 1.00 0.87 0.33 0.26 0.93 0.86 0.39 0.35
Hvy.
F
2.76 2.62 1.44 1.31 0.40 0.34 1.19 1.13 0.55 0.51
Lgt.
E
1.94 1.81 1.00 0.87 0.33 0.26 0.93 0.86 0.39 0.35
Hvy.
F
2.76 2.62 1.44 1.31 0.40 0.34 1.19 1.13 0.55 0.51
Hvy.
F
2.76 2.62 1.44 1.31 0.40 0.34 1.19 1.13 0.55 0.51
} 4.00 1.00
} 4.00 1.00
4.00 1.25
Type B, Style 1
10 (0.1900)
24
…
…
0.97 0.91 0.45 0.39 0.15 0.12 0.39 0.36 0.28 0.22
1⁄ (0.2500)
4
20
…
…
1.16 1.09 0.56 0.50 0.17 0.14 0.47 0.44 0.34 0.28
3.00 0.50
5⁄ (0.3125)
16
18
…
…
1.44 1.38 0.67 0.61 0.18 0.15 0.55 0.52 0.41 0.34
3.00 0.50
2.00 0.50
3⁄ (0.3750)
8
16
…
…
1.72 1.66 0.80 0.73 0.20 0.17 0.63 0.60 0.47 0.41
4.00 0.50
7⁄ (0.4375)
16
14
…
…
2.00 1.94 0.91 0.84 0.21 0.18 0.71 0.68 0.53 0.47
3.00 1.00
1⁄ (0.5000)
2
13
…
…
2.31 2.22 1.06 0.94 0.23 0.20 0.79 0.76 0.62 0.50
3.00 1.00
5⁄ (0.6250)
8
11
…
…
2.84 2.72 1.31 1.19 0.27 0.23 0.96 0.92 0.75 0.62
2.50 1.00
Type B, Style 2
10 (0.1900)
24
…
…
1.01 0.95 0.78 0.72 0.14 0.11 0.39 0.36 0.28 0.22
1⁄ (0.2500)
4
20
…
…
1.22 1.16 0.94 0.88 0.16 0.13 0.47 0.44 0.34 0.28
2.00 0.50
5⁄ (0.3125)
16
18
…
…
1.43 1.37 1.09 1.03 0.17 0.14 0.55 0.52 0.41 0.34
2.00 0.50
3⁄ (0.3750)
8
16
…
…
1.63 1.57 1.25 1.19 0.18 0.15 0.63 0.60 0.47 0.41
2.00 0.50
All dimensions in inches. Sizes shown in bold face are preferred.
1Plain point, unless alternate point from styles shown in Table 8 is specified by user.
a Where specifyin nominal size in decimals, zeros in the fourth decimal place are omitted.
b Hvy. = Heavy; Lgt. = Light; Reg. = Regular.
1.25 0.50
1718
Table 6. American National Standard Types C and D Wing Screws
ANSI B18.17-1968, R1983
TYPE C
TYPE D
A
B
Thds.
per
Inch
Wing
Spread
Max Min
Wing
Height
Max Min
6 (0.1380)
8 (0.1640)
10 (0.1900)
1⁄ (0.2500)
4
32
32
24, 32
20
0.85
0.85
0.85
1.08
0.83
0.83
0.83
1.05
0.45
0.45
0.45
0.56
0.43
0.43
0.43
0.53
0.15
0.15
0.15
0.17
0.12
0.12
0.12
0.14
…
…
…
…
5⁄ (0.3125)
16
3⁄ (0.3750)
8
18
1.23
1.20
0.64
0.62
0.22
0.19
…
16
1.45
1.42
0.74
0.72
6 (0.1380)
8 (0.1640)
10 (0.1900)
1⁄ (0.2500)
4
32
32
24, 32
20
0.85
0.85
0.85
1.08
0.83
0.83
0.83
1.05
0.43
0.43
0.43
0.57
0.42
0.42
0.42
0.53
5⁄ (0.3125)
16
3⁄ (0.3750)
8
7⁄ (0.4375)
16
1⁄ (0.5000)
2
18
1.23
1.20
0.64
0.62
Nominal
Size or
Basic
Screw
Diametera
C
E
F
G
Boss
Dia.
Max Min
Height
Max Min
L
Practical
Screw
Lengths
Max Min
…
…
…
…
0.41
0.41
0.41
0.46
0.39
0.39
0.39
0.44
0.12
0.12
0.12
0.12
0.07
0.07
0.07
0.07
0.75
1.00
1.25
1.50
0.25
0.38
0.38
0.50
…
0.51
0.49
0.14
0.10
1.50
0.50
…
0.63
0.62
0.15
0.12
1.50
0.50
0.36
0.36
0.36
0.42
0.41
0.41
0.41
0.48
0.40
0.40
0.40
0.46
0.20
0.20
0.20
0.23
0.18
0.18
0.18
0.21
1.00
1.00
2.00
2.50
0.25
0.38
0.38
0.50
0.49
0.57
0.55
0.26
0.24
3.00
0.50
Wing
Boss
Thick.
Dia.
Max Min Max Min
Type C, Style 1
0.24 0.21
…
Type C, Style 2
0.14 0.12 0.38
0.14 0.12 0.38
0.14 0.12 0.38
0.16 0.14 0.44
0.20
0.18
0.50
16
1.45
1.42
0.74
0.72
0.23
0.21
0.62
0.60
0.69
0.67
0.29
0.27
3.00
0.75
14
1.89
1.86
0.91
0.90
0.29
0.28
0.75
0.73
0.83
0.82
0.38
0.37
4.00
1.00
13
1.89
1.86
0.91
0.90
0.75
0.73
0.83
0.82
0.38
0.37
4.00
1.00
6 (0.1380)
8 (0.1640)
10 (0.1900)
12 (0.2160)
1⁄ (0.2500)
4
32
32
24
24
20
0.78
0.78
0.90
1.09
1.09
0.72
0.72
0.84
1.03
1.03
0.40
0.40
0.46
0.46
0.46
0.34
0.34
0.40
0.40
0.40
0.29 0.28
Type D
0.18 0.12
0.18 0.12
0.21 0.15
0.26 0.20
0.26 0.20
0.35
0.35
0.35
0.44
0.47
0.31
0.31
0.31
0.39
0.43
0.40
0.40
0.53
0.61
0.61
0.34
0.34
0.47
0.55
0.55
0.21
0.21
0.22
0.24
0.24
0.14
0.14
0.16
0.18
0.18
0.75
0.75
1.00
1.00
1.50
0.25
0.38
0.38
0.38
0.50
5⁄ (0.3125)
16
3⁄ (0.3750)
8
18
1.31
1.25
0.62
0.56
0.29
0.57
0.53
0.68
0.62
0.29
0.23
1.50
0.50
16
1.31 1.25 0.62 0.56 0.29 0.23 0.63 0.59 0.68
0.62
0.29
0.23
2.00
0.75
0.23
Wing Screw and Thumb Screw Designation.—When specifying wing and thumb
screws, the following data should be included in the designation and should appear in the
following sequence: nominal size (number, fraction or decimal equivalent), threads per
inch, length (fractions or decimal equivalents), type, style and/or series, point (if other than
plain point), materials, and finish.
1719
Examples:10—32 × 11⁄4, Thumb Screw, Type A, Regular, Steel, Zinc Plated.
0.375—16 × 2.00, Wing Screw, Type B, Style 2, Steel, Cadmium Plated.
0.250—20 × 1.50, Wing Screw, Type C, Style 2, Zinc Alloy Wings, Steel Shank, Brass
Plated.
Table 7. American National Standard Types A and B Thumb Screws
ANSI B18.17-1968, R1983
TYPE A
A
TYPE B
B
Nominal
Size or
Basic Screw
Diametera
Thds.
per
Inch
Head
Width
Max
Min
6 (0.1380)
8 (0.1640)
10 (0.1900)
12 (0.2160)
1⁄ (0.2500)
4
5⁄ (0.3125)
16
3⁄ (0.3750)
8
32
32
24, 32
24
20
18
16
0.31
0.36
0.42
0.48
0.55
0.70
0.83
0.29
0.34
0.40
0.46
0.52
0.67
0.80
10 (0.1900)
1⁄ (0.2500)
4
5⁄ (0.3125)
16
3⁄ (0.3750)
8
7⁄ (0.4375)
16
1⁄ (0.5000)
2
24
20
18
16
14
13
0.89
1.05
1.21
1.41
1.59
1.81
0.83
0.99
1.15
1.34
1.53
1.72
6 (0.1380)
8 (0.1640)
10 (0.1900)
12 (0.2160)
1⁄ (0.2500)
4
5⁄ (0.3125)
16
3⁄ (0.3750)
8
7⁄ (0.4375)
16
1⁄ (0.5000)
2
32
32
24, 32
24
20
18
16
14
13
0.45
0.51
0.58
0.71
0.83
0.96
1.09
1.40
1.54
0.43
0.49
0.54
0.67
0.80
0.91
1.03
1.35
1.46
10 (0.1900)
1⁄ (0.2500)
4
5⁄ (0.3125)
16
3⁄ (0.3750)
8
7⁄ (0.4375)
16
1⁄ (0.5000)
2
24
20
18
16
14
13
0.89
1.05
1.21
1.41
1.59
1.81
0.83
0.99
1.15
1.34
1.53
1.72
C
Head
Head
Height
Thick.
Max
Min
Max
Min
Type A, Regular
0.33
0.31
0.05
0.04
0.38
0.36
0.06
0.05
0.48
0.46
0.06
0.05
0.54
0.52
0.06
0.05
0.64
0.61
0.07
0.05
0.78
0.75
0.09
0.07
0.95
0.92
0.11
0.09
Type A, Heavy
0.84
0.72
0.18
0.16
0.94
0.81
0.24
0.22
1.00
0.88
0.27
0.25
1.16
1.03
0.30
0.28
1.22
1.09
0.36
0.34
1.28
1.16
0.40
0.38
Type B, Regular
0.28
0.26
0.08
0.06
0.32
0.30
0.09
0.07
0.39
0.36
0.10
0.08
0.45
0.43
0.11
0.09
0.52
0.48
0.16
0.14
0.64
0.60
0.17
0.14
0.71
0.67
0.22
0.18
0.96
0.91
0.27
0.24
1.09
1.03
0.33
0.29
Type B, Heavy
0.78
0.66
0.18
0.16
0.81
0.72
0.24
0.22
0.88
0.78
0.27
0.25
0.94
0.84
0.30
0.28
1.00
0.91
0.36
0.34
1.09
0.97
0.40
0.38
C′
E
Head
Thick.
Max
Min
Shoulder
Diameter
Max
Min
L
Practical
Screw
Lengths
Max
Min
…
…
…
…
…
…
…
…
…
…
…
…
…
…
0.25
0.31
0.35
0.40
0.47
0.59
0.76
0.23
0.29
0.32
0.38
0.44
0.56
0.71
0.75
0.75
1.00
1.00
1.50
1.50
2.00
0.25
0.38
0.38
0.38
0.50
0.50
0.75
0.10
0.10
0.11
0.11
0.13
0.14
0.08
0.08
0.09
0.09
0.11
0.12
0.33
0.40
0.46
0.55
0.71
0.83
0.31
0.38
0.44
0.53
0.69
0.81
2.00
3.00
4.00
4.00
2.50
3.00
0.50
0.50
0.50
0.50
1.00
1.00
0.03
0.04
0.05
0.05
0.06
0.09
0.11
0.14
0.15
0.02
0.02
0.03
0.03
0.03
0.06
0.08
0.11
0.11
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
…
1.00
1.00
2.00
2.00
2.50
3.00
3.00
4.00
4.00
0.25
0.38
0.38
0.38
0.50
0.50
0.75
1.00
1.00
0.08
0.11
0.11
0.14
0.14
0.18
0.06
0.09
0.09
0.12
0.12
0.16
…
…
…
…
…
…
…
…
…
…
…
…
2.00
3.00
4.00
4.00
3.00
3.00
0.50
0.50
0.50
0.50
1.00
1.00
a Where specifying nominal size in decimals, zeroes in fourth decimal place are omitted.
Lengths of Wing and Thumb Screws.—The length of wing or thumb screws is measured parallel to the axis of the screw from the intersection of the head or shoulder with the
shank to the extreme point of the screw. Standard length increments are as follows: For
1720
sizes No. 4 through 1⁄4 inch and for nominal lengths of 0.25 to 0.75 inch, 0.12-inch increments; from 0.75- to 1.50-inch lengths, 0.25-inch increments; and for 1.50- to 3.00-inch
lengths, 0.50-inch increments. For sizes 5⁄16 through 1⁄2 inch and for 0.50- to 1.50-inch
lengths, 0.25-inch increments; for 1.50- to 3.00-inch lengths, 0.50-inch increments; and
for 3.00- to 4.00-inch lengths, 1.00-inch increments.
Threads for Wing Screws and Thumb Screws.—Threads for all types of wing screws
and thumb screws are in conformance with ANSI Standard Unified Thread, Class 2A. For
threads with an additive finish the Class 2A maximum diameters apply to an unplated
screw or to a screw before plating, whereas the basic diameters (Class 2A maximum diameters plus the allowance) apply to a screw after plating. All types of wing and thumb screws
should have complete (full form) threads extending as close to the head or shoulder as
practicable.
Points for Wing and Thumb Screws.—Wing and thumb screws are normally supplied
with plain points (sheared ends). Where so specified, these screws may be obtained with
cone, cup, dog, flat or oval points as shown in Table 8.
Table 8. American National Standard Alternate Points for Wing and Thumb Screws
ANSI B18.17-1968, R1983
CUP POINT
CONE POINT
FLAT POINT
OVAL POINT
DOG POINT
O
P
Nominal
Size or
Basic Screw
Diamtera
Cup and Flat
Point Diameter
Max
Min
Diameter
Max
Min
Max
4 (0.1120)
6 (0.1380)
8 (0.1640)
10 (0.1900)
12 (0.2160)
1⁄ (0.2500)
4
5⁄ (0.3125)
16
3⁄ (0.3750)
8
7⁄ (0.4375)
16
1⁄ (0.5000)
2
5⁄ (0.6250)
8
0.061
0.074
0.087
0.102
0.115
0.132
0.172
0.212
0.252
0.291
0.371
0.075
0.092
0.109
0.127
0.144
0.156
0.203
0.250
0.297
0.344
0.469
0.061
0.075
0.085
0.095
0.115
0.130
0.161
0.193
0.224
0.255
0.321
0.051
0.064
0.076
0.088
0.101
0.118
0.156
0.194
0.232
0.270
0.347
Q
R
Length
Min
Oval Point
Radius
Max
Min
0.051
0.065
0.075
0.085
0.105
0.120
0.151
0.183
0.214
0.245
0.305
0.099
0.140
0.156
0.172
0.188
0.219
0.256
0.312
0.359
0.406
0.500
Dog Pointb
0.070
0.087
0.103
0.120
0.137
0.149
0.195
0.241
0.287
0.334
0.456
0.084
0.109
0.125
0.141
0.156
0.188
0.234
0.281
0.328
0.375
0.469
b The axis of dog points shall not be eccentric with the axis of the screw by more than 3 per cent of the
basic screw diameter or 0.005 in., whichever is the smaller.
1The external point angles specified shall apply to those portions of the angles which lie below the
thread root diameter, it being recognized the angle within the thread profile may be varied due to the
manufacturing processes.

machine screws and nuts - Sport Pilot Information Page

Transcription

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