Difficulty: Easy
Correct Answer: helix angle
Explanation:
Introduction / Context:
Cutting geometry concepts repeat across machining processes. In turning, rake angle controls chip flow and cutting forces. In drilling, chip flow is governed by the drill's flute helix. Understanding the correspondence helps transfer intuition between operations.
Given Data / Assumptions:
Concept / Approach:
Rake angle is the angle that facilitates chip flow off the cutting edge. On a twist drill, the equivalent function is served by the helix angle of the flutes, which determines chip flow direction and effective rake along the cutting lips. Other drill angles (point angle, chisel edge angle, lip clearance) serve different functions.
Step-by-Step Solution:
Identify the function of rake: reduce cutting resistance, guide chip flow.Find the drill feature that controls chip flow similarly → flute helix angle.Conclude helix angle best corresponds to rake angle in turning.
Verification / Alternative check:
Drill design references treat helix as providing positive rake along the lips; altering helix angle changes chip evacuation and cutting forces analogous to changing rake in turning.
Why Other Options Are Wrong:
Common Pitfalls:
Assuming point angle equals rake; overlooking that effective rake along drill lips is a function of helix and point geometry together.
Final Answer:
helix angle
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