Twist drill nomenclature: identify the helix angle vs point angle Evaluate the statement about a twist drill: “The angle included between the two lips, projected on a plane parallel to the drill axis and parallel to the two cutting lips, is called the helix angle.” Decide if this statement is correct or incorrect.

Difficulty: Easy

• Correct — that defines the helix angle
• Incorrect — that is the point angle; helix angle is between flute helix and axis
• Correct only for drills above 20 mm diameter
• Indeterminate without the chisel edge angle