Question 1

MECH 313/N – Engineering Drawing and Design
Section N, Winter 2010
Quiz #2 (18-Feb-2010 – Time: 20 minutes)
Student Name: ____________________________
(Surname
First name)
Student ID: ___________________
Section: NA / NB
Student details must be written in INK.
Question 1 (10 marks)
How are the basic dimensions showing in the drawing?
(Hint: Draw the symbol plus a dimension value to illustrate your answer)
Answer:
100
Question 2 (15 marks)
The limits of size for the diameter of the hole and the geometrical tolerance between the
axis of the hole and Datum A are shown in the Figure.
Determine the virtual condition for the hole.
Answer:
Virtual condition for a hole = MMC – GT
= 15 – 0.05
=14.95mm
DIMENSIONS IN MM.
Question 3 (15 marks)
Calculate the distance between the maximum permissible positions of the hole if the
coordinate tolerancing zone ± .01 inch is specified.
Answer:
Maximum permissible position:
Corner to corner:
= sqrt(( .02x .02)x2) = .028”
From hole centre to corner:
= sqrt(( .01x .01)x2) = .014’
DIMENSIONS IN INCHES
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Question 4 (10 marks)
What is the shape of the positional tolerancing zone?
(Hint: The part will be rejected when its measurements are outside of that zone)
Answer:
O - Circle
Question 5 (20 marks)
Calculate the required positional tolerance for the clearance holes of a bolted assembly,
which is considered to be a floating fastener case. The limits of the bolt diameter are
19.760 – 19.890mm and the limits of the clearance holes are 20.000 – 20.130mm.
Ignoring any perpendicular geometrical tolerance and thermal effects
Answer:
Floating fastener case:
MMC for hole = 20.000mm
MMC for bolt = 19.890mm
Positional tolerance = 20.000 -19.890
= 0.11mm for each part.
Question 6 (30 Marks)
The following specifications need to be applied to the casting surface of a bearing
bracket in the drawing:
 Maximum allowable surface roughness = 0.8μm with a machined allowance of
0.5mm.
A, Draw the surface texture symbol to represent the machining process including the
above specifications.
Answer:
See Table 8-5 for the positions of these two items. No need to write the unit. Just write
0.5 for machined allowance and 0.8 for the surface roughness
B, Suggest a machining process which will achieve the above specified surface
roughness.
Answer:
Turning, grinding and boring etc. Check out Tables 8-6 and 8-7.
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