Lathe finishing practice After which machining operation is chamfering considered essential to remove burrs, protect the edge, and facilitate assembly?

Introduction / Context:
Chamfering produces a small, angled surface that removes sharp edges and burrs. It is especially crucial where the geometry must allow easy engagement with mating parts, such as bolts, nuts, and screwed holes. Correct sequencing of chamfering improves safety, function, and appearance.

Given Data / Assumptions:

• Operation performed on a lathe or machining center.
• Threads are newly cut on an external or internal feature.
• Goal is reliable assembly and protection of thread crests/starts.

Concept / Approach:
After thread cutting, a burr typically forms at the entry and exit. A chamfer at the thread start guides the fastener, reduces cross-threading, and prevents the first thread from damage. Standards for fasteners specify chamfering before gauging or assembly to ensure smooth engagement.

Step-by-Step Solution:

Verification / Alternative check:
Workshop practice and standards recommend 30–45 degree chamfers on threaded ends and at the mouth of tapped holes.

Why Other Options Are Wrong:
Knurling: produces a rough grip; chamfer not essential afterward.Rough turning: deburring may be needed, but chamfer is not always essential.Boring: internal sharp edges may be lightly broken, yet it is not as critical as after threading.Parting-off: edges are typically deburred; a chamfer is situational, not essential.

Common Pitfalls:
Skipping chamfer leads to damaged first thread and assembly difficulty. Over-chamfering may reduce engagement length and weaken the thread start.

Final Answer:

Thread cutting