Types and Uses of Fasteners
Transcription
Types and Uses of Fasteners
Types and Uses of Fasteners Copyright © Texas Education Agency, 2011. All rights reserved. Importance of Fasteners • They simplify the manufacture of machines and structures. • They reduce the need for large one piece parts. • It is normally easier to make less complex components and fasten them together Copyright © Texas Education Agency, 2011. All rights reserved. Importance cont. • They simplify repair of structures and equipment. • Individual component parts can simply and quickly be separated for inspection, repair, or replacement. Copyright © Texas Education Agency, 2011. All rights reserved. They Provide Safety • Use of fasteners tends to assure that once an assembly is fastened together it will hold together. • They can also be installed to provide additional support or they be a weak links. (Ex. Shear pins, drive shafts, & breakaway plowshares) Copyright © Texas Education Agency, 2011. All rights reserved. B. General types of Fasteners • Bolts, nuts, and washers • Screws • Keys • Studs • Pins • Rings • Rivets • Adhesives • Nails • etc. Copyright © Texas Education Agency, 2011. All rights reserved. Specific Types and uses of fasteners • Bolts: are threaded lengths of steel rod with heads on one end. • They are used with a nut at the other end and sometimes with a washer as well. Copyright © Texas Education Agency, 2011. All rights reserved. American Standard Bolts Hexagon or Square Head • Most have a hexagonal head (6-sided). Older square bolts have a 4- sided head. • Without a nut they are called cap screws and are screwed into threaded holes. • Bolts are selected by strength rating, chemical or heat compatibility. Copyright © Texas Education Agency, 2011. All rights reserved. Carriage Bolts • Most have a round head with a square neck, under the head. • Carriage bolts are used to fasten wood parts where a smooth finish is required. Copyright © Texas Education Agency, 2011. All rights reserved. Bolts Carriage bolt Plow bolt Cap Screw Hex Bolt Copyright © Texas Education Agency, 2011. All rights reserved. Plow Bolts • Counter sunk, square- neck carriage bolt. • These have a flat, tapered head that fit into countersunk holes. • Used when it is necessary for the head to lie flush with the surfaces of the part. Copyright © Texas Education Agency, 2011. All rights reserved. Nuts: • Are flat, usually hexagonal shaped steel pieces with internally cut threads. Copyright © Texas Education Agency, 2011. All rights reserved. Castellated & Slotted nuts • A. These are used when a cotter pin is placed through a hole in the bolt to secure the nit so it cannot come loose. • Ex: Wheel bearing spindles Copyright © Texas Education Agency, 2011. All rights reserved. Nuts Copyright © Texas Education Agency, 2011. All rights reserved. Self Locking nuts • A. Once tightened these nuts stay firmly in place. • B. They are commonly known as “elastic” or plastic insert nuts. Copyright © Texas Education Agency, 2011. All rights reserved. Washers • A. Plain washers: (flat washers) are steel disks with a hole in the center. • B. They are used to reduce the stress under the bolt or nut. • C. They spread a clamping force from the bolt over a larger area to span slots and oversize holes in wood Copyright © Texas Education Agency, 2011. All rights reserved. Washers Copyright © Texas Education Agency, 2011. All rights reserved. Lock Washers • A. Helical spring washers are made of tough spring steel. • B. Normally installed under the nut or bolt. • C. They are used to prevent rotation of the nut. Copyright © Texas Education Agency, 2011. All rights reserved. Nails • Nails are steel rods with a head on one end and usually pointed at the other end. • They are used primarily to join wood together. Copyright © Texas Education Agency, 2011. All rights reserved. Nail size: • Generally given in terms of “penny” • “d” indicates the penny size • Nails are sold by the pound at most hardware stores. Copyright © Texas Education Agency, 2011. All rights reserved. Penny Sizes Number per pound Penny 2d 3d 4d 8d 10d 16d 20d Length (In) 1 1¼ 1½ 2 3 3¼ 4 Common 830 578 316 168 106 69 49 Box 8010 635 473 236 145 84 71 Finish 13151 807 584 309 189 121 90 Copyright © Texas Education Agency, 2011. All rights reserved. Common Nail • This is a general all purpose construction nail suitable for framing structures. • It has a larger diameter than the same size box nail Copyright © Texas Education Agency, 2011. All rights reserved. Common Nail Copyright © Texas Education Agency, 2011. All rights reserved. Box Nail • Box Nail are used for end nailing and light household use. • The point is dulled to prevent splitting the wood Copyright © Texas Education Agency, 2011. All rights reserved. Box Nails Copyright © Texas Education Agency, 2011. All rights reserved. Finish Nail • This is a nail with a small head with a dimple in the center to allow for countersinking with a nail set. Copyright © Texas Education Agency, 2011. All rights reserved. Finish Nail Copyright © Texas Education Agency, 2011. All rights reserved. Duplex Nails • A duplex nail has two heads on the shank • It is used to whenever a nail has to be removed. • Ex when assembling concrete forms Copyright © Texas Education Agency, 2011. All rights reserved. Duplex Nail Copyright © Texas Education Agency, 2011. All rights reserved. Roofing Nails • Used to secure shingles or roofing to the underlying structure • They are normally available with either a spiral or helix head shank for extra holding power. Copyright © Texas Education Agency, 2011. All rights reserved. Roofing Nail Copyright © Texas Education Agency, 2011. All rights reserved. Screws • Screws are threaded lengths of steel rod with heads on one end. • Screw heads may be slotted, cross slotted, square, or hexagonal. Copyright © Texas Education Agency, 2011. All rights reserved. Types of screws Copyright © Texas Education Agency, 2011. All rights reserved. (c) 2006 Texas Trade & Industrial Education UNT in partnership with TEA, Copyright ©. All rights reserved. Building Trades: Fasteners