This set of Machine Tools Multiple Choice Questions & Answers (MCQs) focuses on “Drilling Operation-1”.

1. A hole is being drilled with 5 mm drill at a feed of 0.1 mm/revolution and rpm is 200. Calculate the metal removal rate (m) in mm^{3}/minute.

a) 392.5

b) 785

c) 1570

d) none of the mentioned

View Answer

Explanation: Here, we have the value of diameter, feed and rpm. So, from the formula, m= ( 3.14*d*d*f*n) / 4, we can easily get the value of metal removal rate.

2. If drill is 2.5 mm, feed is 0.35 mm/revolution and metal removal rate is 40 mm^{3}/minute. Then find out the value of rpm.

a) 46.6

b) 23.3

c) 93.2

d) 11.65

View Answer

Explanation: From the formula, m= ( 3.14*d*d*f*n) / 4. From this formula, we can easily calculate rpm. Rpm means revolution per minute.

3. If drill is 5.5 mm, metal removal rate is 65 mm^{3}/minute and rpm is 130.Then find the value of feed in mm/revolution.

a) 0.02

b) 0.2

c) 0.04

d) 0.4

View Answer

Explanation: Feed is the distance the drill moves into the work at each revolution of the spindle. From the formula, m= ( 3.14*d*d*f*n) / 4, we can easily calculate feed.

4. If metal removal rate is 120 mm^{3}/minute, rpm is 105 and feed is 0.1 mm/revolution. Then find the value of drill in mm.

a) 14.6

b) 3.8

c) 7.6

d) 1.9

View Answer

Explanation: From the formula, m= ( 3.14*d*d*f*n) / 4, we can calculate the value of drill.

5. If value of the diameter of the drill (d2) = 10mm, then find the value of the depth of cut (d1).

a) 5

b) 10

c) 20

d) none of the mentioned

View Answer

Explanation: Value of diameter of the drill is always twice to that the value of the depth of cut. From the formula, d1= d2/2.

6. The diameter of the drill is 15 mm and rpm of drill is 5. Find the value of cutting speed in meter/minute.

a) 235.5

b) 0.2355

c) 0.075

d) 75

View Answer

Explanation: From the formula, cs = (3.14*d*n) /1000. Cutting speed is the peripheral speed of the drill.

7. Rpm is 10 and feed per revolution (f2) is 5. Then find the value of feed per minute (f1).

a) 2

b) 4

c) 1

d) none of the mentioned

View Answer

Explanation: Rpm = f1/f2. Here rpm=10 and f2=5. So value of f1 should be 50.

8. If depth of cut is 20 mm, then find the value of diameter of the drill.

a) 10

b) 20

c) 40

d) none of the mentioned

View Answer

Explanation: Depth of cut=diameter/2. It is simply a distance.

9. Feed per minute (f1) is 20 and rpm (n) is 5. Then find the value of feed per revolution (f2).

a) 2

b) 4

c) 1

d) 0.5

View Answer

Explanation: Rpm = f1/f2. Here f1=20 and n=5. So, f2 should be 4.

10. If t=2minute, n=2rpm and s=5 mm. Then find the value of l. t=machining time in minute, l=length of travel of the drill in mm, n= rpm of the drill and s=feed per revolution of the drill in mm.

a) 5

b) 10

c) 20

d) none of the mentioned

View Answer

Explanation: From the formula, t= l / (n*s). Here t=2, n=2 and s=5. Put all these values with their units in the mentioned equation,you will easily get the answer as 20 mm.

11. If d=2, n=1 and f=2. Then find the value of m. d= diameter of drill in mm, n=rpm, f=feed per revolution in mm and m=metal removal rate in mm^{3}/minute.

a) 3.14

b) 6.28

c) 12.56

d) none of the mentioned

View Answer

Explanation: From the formula, m= (3.14*d*d*n*f) / 4, we can easily get the value of m. Metal removal rate means the rate at which the metal is removed during the operation.

12. If d=2, n=2 and m=3. Then find the value of f. d= diameter of drill in mm, n=rpm, f=feed per revolution in mm and m=metal removal rate in mm^{3}/minute.

a) 0.238

b) 0.477

c) 0.119

d) none of the mentioned

View Answer

Explanation: From the formula, m= (3.14*d*d*n*f) / 4, we can easily get the value of feed. Feed may also be expressed as feet per minute or mm/minute.

13. If m=5, n=2 and f=3. Then find the value of m. d= diameter of drill in mm, n=rpm, f=feed per revolution in mm and m=metal removal rate in mm^{3}/minute.

a) 1.03

b) 1.065

c) 0.266

d) none of the mentioned

View Answer

Explanation: From the formula, m= (3.14*d*d*n*f) / 4, we can easily find the value of m.

14. If cs=0.942 and d=60, then find the value of n. d=diameter of drill in mm, n=rpm and cs=cutting speed in mm/minute.

a) 15.7

b) 15700

c) 5

d) 5000

View Answer

Explanation: From the formula, cs = (3.14*d*n) /1000, we can easily find value of n. N means rpm-revolution per minute. It is an important term in any operation.

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