Q91
The point angle of a drill, for drilling stainless steel, is
A.
90°
B.
118°
C.
135°
AnswerD.
150°
Answer: Option C
Solution
Answer: Option C
Solution:
The point angle is located at the head of the twist drill.
For hard materials such as stainless steel, the point angle should be large and e.g. 130° or 135°.
For soft materials, point angles of e.g. 118° are used.
With a large point angle, more of the cutting edge engages in the workpiece when drilling