CONCORDIA UNIVERSITY
FACULTY OF ENGINEERING AND COMPUTER SCIENCE
Department of Mechanical and Industrial Engineering
FINAL EXAMINATION- MACHINE DRAWING AND DESIGN, MECH 313/4, WINTER 2010
Instructors: Dr. Javad Dargahi, Dr. Sivakumar Narayanswamy, Dr. John Cheung, Dr. Suraj Joshi
Open book examination
Date of the examination: April 19, 2010
Duration of the examination: 3 hours
Maximum Marks: 100
Materials allowed: Faculty approved calculators, Text book, Copy of bearing tables and limits and fits
tables for Metric system.
Answer the questions in the space provided
Student’s first name: . . . . . . . . . . . . . . . . . . . . . . . .
Student’s surname: . . . . . . . . . . . . . . . . . . . . . .
I.D. #: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section: . . . . . . . .
Signature: . . . . . . . . . . . . . . . .
Question 1 (20 multiple choice questions - 20 marks)
1.
What is the meaning of the adjacent symbol on the drawing?
A.
Removal of material by a specific machining process
B.
Removal of material by any machining process
C.
No removal of material
D.
Removal of material applies to all around the profile
2.
A pin is fitted into a bushed hole. An RC4 close
running fit is required for the pin of .5 inch
diameter. What is the maximum clearance
between the pin and the bushed hole?
A.
.0017”
B.
.0033”
C.
.0013”
D.
.0023”
1
3.
How is a group of holes, equally spaced on a pitch circle diameter (PCD), represented on a drawing
according to the standard practice?
A.
Draw all the holes equally spaced on the PCD
B.
Draw only the center of all the holes equally spaced on the PCD
C.
Draw two or three holes and only the centre for the rest equally spaced on the PCD
D.
Write a local note for the group of holes
4.
Select the machining process which is likely to achieve the surface finish of 0.4µm
A.
Drilling
B.
Milling
C.
Forging
D.
Grinding
5.
Calculate the maximum and minimum lengths respectively of
Feature A, shown in the drawing.
A.
25.25, 24.25
B.
25.00, 24.25
C.
25.25, 24.50
D.
None of above
6.
Which of the following statement(s) about retaining rings is (are) correct?
i)
Retaining Rings provide movable shoulder to locate, retain, or lock components on
shafts and in bores of housing
ii)
Retaining Rings are used in components like bearings on shaft and Housings
iii)
Retaining Rings are made of spring steel.
iv)
Retaining Rings have low shear strength.
A.
B.
C.
D.
7.
i, ii, iii, iv
i, ii, iii
i, iv
ii, iv
Which of the following is incorrect?
A.
The width of the square and flat key should be approximately one-quarter the shaft
diameter.
B.
Gib-Head Key: Same as Square keys, with a head for easy removal.
C.
The Pratt and Whitney key is rectangular with rounded ends. One third of this key sits in the
shaft and two-third sits in the hub.
D.
Woodruff key: Semicircular key seat in the shaft and rectangular key way in hub and half
width extends into the hub.
2
8.
Angular-contact thrust bearings will support:
A.
A light thrust load in one direction combined with a light radial load
B.
A heavy thrust load
C.
A heavy thrust load in one direction, combined with a moderate radial load
D.
Moderate radial load and a heavy thrust load in two directions
9.
Which of the following statement(s) about rivets is (are) correct?
i)
The rivet length to-diameter ratio should not exceed 6: 1
ii)
Edge distance is the interval between the edge of the part and the edge of the rivet
A.
B.
C.
D.
i
ii
i and ii
Neither i nor ii
10.
From the figure, find the maximum allowable
distance between axes of the features if considered
feature size is 24.9mm and the datum feature is
14.98mm
A.
.04 mm
B.
.06 mm
C.
.08 mm
D.
.12 mm
11.
Which of the following statement(s) about resistance-weld fasteners is (are) correct?
i)
The materials to be joined, both part and fastener, must be similar materials
ii)
The parts to be welded must be portable enough to be carried to the welder
iii)
Production volume should be great enough to justify tooling costs.
A.
B.
C.
D.
12.
i
i and ii
i, ii, iii
ii, iii
What is the virtual condition of the following part?
A.
1.497
B.
1.503
C.
1.505
D.
1.511
3
13.
What would be the size of the gaging element to evaluate Datum
A given the drawing callouts and the measured size of the Datum
Feature A =  34.52mm?
A.
34.40
B.
34.52
C.
35.00
D.
35.20
14.
Which is the correct method for indicating the straightness
tolerance on an axis of the cylinder?
15.
Which of the following symbols can be used to control coaxiality?
A.
B.
C.
D.
All of the above
4
16.
Which of the following conventions for thread representations is used in enlarged assembly
drawings?
A.
Detailed
B.
Enlarged
C.
Simplified
D.
Schematic
17.
Which of the following best describes the purpose of setscrews?
A.
permanent fastening for holding a gear against rotational forces
B.
temporary fastening for holding a gear against rotational forces
C.
permanent fastening for holding a gear against slip forces
D.
All of the above
18.
Washers serve all of the following purposes except
A.
surface protection
B.
hermetic sealing
C.
insulation
D.
all of the above
19.
Which of the following statements is true?
A.
the axes of two sprockets in a chain drive can never be mutually orthogonal
B.
sprockets do not help transmit rotational kinetic energy
C.
Axis of 2 gears can never be orthogonal
D.
Belt drives are used in high temperature environment
20.
In a rack and pinion arrangement,
A.
the rack is a spur gear while the pinion is a linear gear
B.
the rack is a linear gear while the pinion is a spur gear
C.
both the rack and pinion are linear gears
D.
both the rack and pinion are spur gears
Question 2. (15 marks)
Complete the assembly shown in the figure below by adding suitable retaining rings according to the
information supplied. Refer to the appendix and show on the drawing the groove sizes, ring numbers
and dimensions of the key. Scale the drawing for dimensions not shown.





External radial assembly retaining rings mounted on the shaft is to act as a shoulder for the shaft
support
An external axial retaining ring is required to hold the gear on the shaft
Motion of the shaft is transferred to the gear by a square key
Identify the fastener and dimension using proper methods
What is the bearing that in between the shaft and the shaft support known as?
5
Question 3. (25 marks)
Complete the figure of the stepped shaft given in the next page, with the information below.
All datums and tolerances are to be on MMC basis unless otherwise specified.








The end face A of Ø 90 is Datum A. It is to be flat within 0.25mm
The shaft B (Ø 44) is Datum B. It has an h6 sliding fit. Show the limits of size for B. It also has a
straightness tolerance of 0.1mm.
The shaft F (Ø 20) has an h9 free running fit. Show the limits of size for shaft diameter F.
The width of the slot C is datum C. The width is 18.00 – 18.20mm. It is perpendicular within
0.05mm to Datum A. It also has a positional tolerance of 0.1mm and is referenced to Datums A,
and B in that order.
The two holes D (Ø 12) are equally spaced on Ø 68mm. These two holes must not vary from
their true positions by more than 0.2mm and are referenced to Datums A, B and C in that order.
The two holes E (Ø 8) are equally spaced on Ø 68mm. They have a positional tolerance of 0.1mm
and are referenced to Datums A, B and C in that order.
The surface of the end face A of Ø 90 has a machining surface roughness value of 0.8μm and a
machining allowance of 0.15mm.
The shaft surfaces of both diameters B (Ø 44) and F (Ø 20) are to have a surface finish of 0.4μm.
6
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Question 4. (25 marks)
Complete the full section working drawing of the sliding gear speed reducer shown in the figure on the
following page. Support the input and output shafts on journal bearings and the counter shaft on ball
bearings. The gears are held to the shafts by setscrews and woodruff keys. You only need to show the
general bearing symbol for ball bearings and identify the bearing number and the Woodruff key number
from the tables. Gears C and D are combined into one part and slide on the countershaft. Complete the
chart on the figure showing the two speeds available (when gears C and E mesh and when gears F and D
mesh) for the different motor inputs. Use your judgment for dimensions not shown. The drawing is not
to scale.
Gear
A
B
C
D
E
F
# of Teeth
20
30
20
24
30
26
INPUT
RPM
OUTPUT
RPM
1150
GEARS IN
CONTACT
COUNTER
SHAFT RPM
F&D
E&C
1750
F&D
E&C
8
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Question 5. (15 marks)
The head shaft of an apron conveyor, which handles rough castings from a shakeout, operates at 66 rpm
and is driven by a gear motor whose output is 5.6 kW at 100 rpm. The diameter of the head shaft is 50
mm, and the diameter of the gear motor shaft is 44 mm. The center distance between shafts should not
exceed 1055 mm. Select a triple-strand chain (for moderate shock).
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