1. Calculate the accurate belt length for the following: Large diameter pulley is 11.25" and the small
diameter pulley is 6.125". Shaft centers are 17.5" apart.
a. 62.65"
b. 62.00"
c. 73.98"
d. 62.28" - Answers a. 62.65"
L=2C+1.57(D1+d2)+[(D1-d2)²/4C]
L=2(17.5)+1.57(11.25+6.125)+[(11.25-6.125)²/4(17.5)]
L=35+27.27875+(26.265625/70)
L=62.65
2. The clearance of meshing gears of any diametral pitch is known as:
a. Back lash
b. Tolerance
c. Dedendum
d. Addendum - Answers a. Back lash
3. A Babbitt bearing percentage refers to its area of contact. This is found by:
a. Feeler gauges
b. Plastic gauge
c. Bluing
d. Lead wire - Answers c. Bluing
4. A bearing with a "K" it denotes a tapered bearing. This is held in place by:
,a. Shaft collar
b. A tapered adapter sleeve
c. Lock nut
d. Thread locker - Answers b. A tapered adapter sleeve
5. An 8" pulley turns at 120 RPM and drives a second pulley at 150 RPM. What is the driven pulley
diameter?
a. 4.6"
b. 6.4"
c. 8.3"
d. 3.8" - Answers b. 6.4"
120RPM/150RPM = 0.8 ratio
0.8 x 8" = 6.4"
6. The letters A, B, C on a sprocket refers to:
a. Tooth size
b. Pitch
c. Hub Class
d. Type of chain - Answers c. Hub Class
7. Crowning on a pulley is used for:
a. Decreased wear
b. Tension
c. Self alignment
,d. To allow for different classes of belts - Answers c. Self alignment
8. The standard taper on an imperial key is:
a. 1:100
b. 1:96
c. 1:4
d. 1:25 - Answers b. 1:96
9. A type of bearing mounted face to face and back-to-back is:
a. Angular contact
b. Conrad
c. Ball
d. Pillow Block - Answers a. Angular contact
10. A bearing with a code of SKF 6212 has a bore of:
a. 12mm
b. 1⁄2"
c. 60mm
d. 62mm - Answers c. 60mm
11. A belt is wrapped around a 6.25" pulley and has 220 degrees of contact. How much of the belt is
contacting the pulley? (Use 3.14159 for pi)
a. 12"
b. 11.999"
c. 12.999"
d. 3.250" - Answers b. 11.999"
, Circumference = 6.25 x 3.14...
= 19.634.../360º
= 0.05454"/º x 220º
= 11.999"
12. A #60 chain has a pitch of:
a. 1⁄2"
b. 3⁄4"
c. 5/8"
d. .625" - Answers b. 3⁄4"
6/8 = 3/4
The left-hand digit denotes the number of eighths of an inch that make up the pitch
#40 = 0.5"
#80 = 1"
#160 = 2"
#240 = 3"
13. In a number 65 chain, the 5 refers to:
a. The use of an offset link
b. That the chain is roller-less
c. That the chain is heavy duty