This set of Machine Tools and Machining Multiple Choice Questions & Answers focuses on “Lathe : Numericals”.

1. Determine the rpm(n) of the shaft. diameter(d)=25 mm, cutting speed(cs)=50 m/min.

a) 636.9

b) 202.83

c) 10.615

d) none of the mentioned

View Answer

Explanation: From the formula, cs= (3.14*d*n)/1000. By putting value of d and cs in above formula, we can easily calculate the value of n.

2. Determine the diameter(d) of the shaft in mm. rpm(n)=25 mm/revolution, cutting speed(cs)=100 mm/min.

a) 21.23

b) 405.47

c) 1273.2

d) none of the mentioned

View Answer

Explanation: From the formula, cs= (3.14*d*n)/1000. Put n=25 and cs=100 in above equation. We can easily get d as 1273.2 mm.

3. Determine the cutting speed(cs) of the shaft mm/min. diameter(d)=25 mm, rpm(n)=50 mm/revolution

a) 3.925

b) 1.25

c) 7.85

d) none of the mentioned

View Answer

Explanation: From the formula, cs= (3.14*d*n)/1000. By putting all mentioned values in above equation, we can easily get value of cutting speed.

4. If the diameter of the work surface before machining(d1) is 100 mm and diameter of the machined surface(d2) is 50 mm.

Then the depth of the cut is______ mm.

a) 50

b) 25

c) 15

d) none of the mentioned

View Answer

Explanation: From the formula, depth of cut=(d1-d2)/2. Here 100-50 equal to 50 and by dividing it by 2 we can get value of depth of cut as 25.

5. Find the metal removal rate from the given data (in mm*mm*mm/minute). cutting speed(cs) =50 mm/minute, depth of cut(d)=10mm, feed(f)= o.1 mm/revolution.

a) 50

b) 500

c) 5000

d) none of the mentioned

View Answer

Explanation: From the formula, metal removal rate=(cs*d*f). Put the value of cs, d, f in the above equation and you can easily get the value of mrr as 50.

6. Find the cutting speed from the given data (in mm/minute). metal removal rate(mrr) =50 mm*mm*mm/minute, depth of cut(d)=1mm, feed(f)= o.1 mm/revolution.

a) 50

b) 500

c) 5000

d) none of the mentioned

View Answer

Explanation: From the formula, metal removal rate= (cs*d*f). Put all the values in above equation and you can get the value of cutting speed.

7. Find the feed from the given data (in mm/revolution). cutting speed(cs) =50 mm/minute, depth of cut(d)=100mm, metal removal rate(mrr)= 10 mm/revolution.

a) 0.2

b) 0.02

c) 0.002

d) none of the mentioned

View Answer

Explanation: From the formula, metal removal rate=(cs*d*f). By putting all values in given equation, you can get the value of feed as 0.002 mm/revolution.

8.Number of revolution = 50, rpm = 100. Find out the machining time.

a) 0.5

b) 2

c) 4

d) none of the mentioned

View Answer

Explanation: Machining time= revolution/rpm. Here revolution is 5o and rpm is 100. 50/100 =0.5 .

9.The larger diameter of shaft is 125 mm and smaller diameter of the shaft is 95 mm. Find the taper. Assume that length of the job and taper is same.

a) 30

b) 15

c) 60

d) none of the mentioned

View Answer

Explanation: Taper= (larger diameter-smaller diameter)/2. 125-95=30 and 30/2=15.

10. Pitch of work piece threads=2, pitch of the lead screw threads=4.

Then, (driver gear/driven gear) =?

a) 2

b) 4

c) 0.5

d) none of the mentioned

View Answer

Explanation: (Driver gear/driven gear) = (Pitch of work piece threads/ pitch of the lead screw threads=4). Put the given values in above equation and you will obtain the value of ratio as 0.5 .

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