Machine Tools and Machining question bank on “Classification of Drilling Machine : According to the Helix Angle of the Flutes”.
1. Helix angle also governs the rack angle.
a) true
b) false
Answer: a
Clarification: This is true. The angle between the helix and axial line on the right is known as helix angel.
2. For cutting ductile material with a long chip, ______ helixangle is necessary.
a) small
b) moderate
c) long
d) none of the mentioned
Answer: c
Clarification: Long helix angle is used for cutting ductile materials with a long chip.
3. Large helix angle ensures the _______ in cutting force.
a) increment
b) reduction
c) can’t say anything
d) none of the mentioned
Answer: b
Clarification: It is the property of it. Helix angles are used in power transfer and in motion conversation in mechanical engineering.
4. For spade drill, ______ helix angle is used.
a) small
b) large
c) zero
d) none of the mentioned
Answer: c
Clarification: Zero helix angle is used for this purpose.Spade drill is a two fluted drill. The external flute provide efficient chip removal.
5. For hard materials, ______ helix angle is used.
a) small
b) large
c) zero
d) none of the mentioned
Answer: a
Clarification: Small helix angle is used for this purpose. In screws, helical gears and warm gears, we uses this helix angle.
6. For micro drill, ______ helix angle is used.
a) small
b) large
c) zero
d) none of the mentioned
Answer: c
Clarification: Zero helix angel is used for this purpose. Helix angel is like a angel between tangent to a helix and an axial line on the right.
7. Which helix angle is used for deep hole drilling?
a) small
b) large
c) zero
d) none of the mentioned
Answer: b
Clarification: Large helix angel is used for this purpose. Zero helix angel are used for small drilling.
8. Which helix angle is used for making holes in very soft materials?
a) small
b) large
c) zero
d) none of the mentioned
Answer: b
Clarification: Large helix angel is used for this purpose as it can make make deep holes easily without any extra effort.
9. According to the helix angel of the flutes, drill can be classified as_____
a) small helix
b) large helix
c) zero helix
d) all of the mentioned
Answer: d
Clarification: Drill can be classified in number of ways. based on helix angel, based on number of flutes, based on materials, based on size on so on. Based on helix angel, it can be classified as small helix, large helix and zero helix.
10. If we increase the helix angle, strength of drill will______
a) increase
b) decrease
c) not affected
d) none of the mentioned
Answer: b
Clarification: There is an inverse relationship between helix angel and strength of drill. If we increase the helix angel, strength of drill will decrease and vice versa.
11.Chip disposal will be better If we _______ the helix angle.
a) increase
b) decrease
c) can’t say anything
d) none of the mentioned
Answer: a
Clarification: It is the property of helix angel and if we decrease the helix angel it will affect chip disposal rate in a negative way.
12. What is the range of the usual helix angle?
a) 10 to 25
b) 20 to 35
c) 45 to 60
d)none of the mentioned
Answer: b
Clarification: 20 to 35-This is the usual range for usual helix angel.
13. What is the range of the large helix angle?
a) 10 to 25
b) 20 to 35
c) 45 to 60
d) none of the mentioned
Answer: c
Clarification: 45 to 60-This is the usual range for usual helix angel.
14. If we increase the helix angle, rack angle will______
a) increase
b) decrease
c) not affected
d) none of the mentioned
Answer: a
Clarification: There is a direct relationship between helix angel and rack angel. If we increase the helix angel, rack angel will also increase and vice versa.
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