What condition indicates that the drill point has proper clearance between the lips?

What condition indicates that the drill point has proper clearance between the lips?

• A. The lips are the same length and angle
• B. The lips have different lengths
• C. The margins are worn
• D. The drill is dull

Answer: (A)

When the two cutting lips of a drill point are the same length and angle, they share the relief behind them evenly, giving proper clearance on both edges. This symmetry lets each lip cut cleanly without rubbing the workpiece, so the drill feeds true and holes come out consistent. If the lips were different lengths, one edge would cut more or rub longer, causing chatter and an uneven hole. Worn margins or a dull drill indicate edge degradation, not balanced clearance between the lips. So the balanced, equal-length and equal-angle lips best indicate proper clearance.

When the two cutting lips of a drill point are the same length and angle, they share the relief behind them evenly, giving proper clearance on both edges. This symmetry lets each lip cut cleanly without rubbing the workpiece, so the drill feeds true and holes come out consistent. If the lips were different lengths, one edge would cut more or rub longer, causing chatter and an uneven hole. Worn margins or a dull drill indicate edge degradation, not balanced clearance between the lips. So the balanced, equal-length and equal-angle lips best indicate proper clearance.