MCQ Question on Design of Machine Tool Gearbox

1. A machine tool has minimum speed of 100 r.p.m. How many speed steps are required by it to achieve speed of 200 rpm? (Geometric progression ratio = 1.06)

a. 11
b. 12
c. 13
d. 14

Answer: b. 12

2. What is the maximum percentage loss of economic cutting speed if geometric progression ratio = 1.06 ?

a. 17.0 %
b. 11.5 %
c. 5.7 %
d. 2.9 %

Answer: d.  2.9 %

3. Diameter range is high in geometric progression due to _________ spindle speed.

a. low
b. high
c. constant
d. none of the above

Answer: a. low

4. What is harmonic progression?
a. Difference between reciprocal of two successive spindle speeds is constant
b. Difference between two successive spindle speeds is constant
c. Ratio of two successive spindle speeds is constant.
d. Ratio of two successive spindle speeds is variable.

Answer: a. Difference between reciprocal of two successive spindle speeds is constant

5. Ratio of two spindle speeds is constant in _________ progression.
a. Arithmetic
b. Geometric
c. Harmonic
d. None of the above

Answer: b. Geometric

6. What is the purpose of using a gear box?
a. To increase torque
b. To increase speed
c. Converts single input speed into multiple output speeds
d. All of the above

Answer: d. All of the above

7. Which of the following statements is true for structure/speed diagrams?
a. Structure diagrams gives range ratio of spindle speeds
b. Speed diagrams do not give range ratio of spindle speeds
c. Speed diagrams consider motor speed
d. All of the above

Answer: c. Speed diagrams consider motor speed

8.  Maximum and minimum diameter of a shaft to be machined is 100 mm and 80 mm respectively. What is the maximum spindle speed if cutting velocity is 40 m/min?
a. 120 r.p.m
b. 127 r.p.m
c. 160 r.p.m.
d. 636 r.p.m.

Answer: c. 160 r.p.m.

9. Economic cutting speed is minimum if geometric ratio is _________
a. minimum
b. maximum
c. equal to economic cutting speed
d. none of the above

Answer: a. minimum

10)   What is the geometric progression ratio if maximum and minimum spindle speeds are 500 r.p.m and 300 r.p.m respectively? (Number of speed steps = 7)
a. 0.91
b. 1.5
c. 1.08
d. 2.0

Answer: c. 1.08