Twist drill geometry — typical chisel edge angle For standard twist drills used on steels, the chisel edge angle is generally taken in the range:

Introduction / Context:
The chisel edge of a twist drill is the web intersection at the drill point. Its angle affects thrust force and chip initiation near the drill axis. Recognizing typical ranges helps in sharpening and selecting drills for different materials.

Given Data / Assumptions:

• Standard two-flute twist drill.
• General-purpose drilling of steels.
• Conventional point geometries without split points or special grinds.

Concept / Approach:
Typical practice uses a chisel edge angle in the range of about 120°–135°. Larger chisel angles (with proper web thinning) help reduce rubbing and thrust; smaller angles can increase axial force. Point angle (often 118°–135°) is related but distinct from the chisel edge angle; both define the drill’s cutting behavior.

Step-by-Step Solution:
Differentiate between point angle and chisel edge angle.Recall the common chisel edge range used on steels.Select 120° to 135° as the standard range.

Verification / Alternative check:
Toolroom references show chisel edge angles commonly paired with 118°–135° point angles, with web thinning to reduce thrust and improve centering.

Why Other Options Are Wrong:
Other ranges do not reflect mainstream practice for general-purpose twist drills and would lead to poor cutting or excessive thrust.

Common Pitfalls:
Confusing chisel edge angle with point angle; they influence different aspects of the drill tip geometry.

Final Answer:
120° to 135°