Lathe workholding: A mandrel is primarily used to hold which type of work for turning the outside accurately?

Introduction / Context:
Mandrels are arbors inserted into a preformed hole so that the outside surface can be turned truly concentric with that hole. They are widely used when the workpiece is thin or delicate and cannot be gripped rigidly by a chuck without deformation.

Given Data / Assumptions:

• The work already has a through hole or bore.
• Goal is accurate external turning concentric to that bore.
• Deformation risk exists if jaws clamp directly on the outside.

Concept / Approach:
By expanding or driving the mandrel into the bore, the work is supported internally along its length, minimizing distortion. Thin rings, pulleys, and bushings are classic use cases.

Step-by-Step Solution:

Verification / Alternative check:
Shop manuals list mandrel applications specifically for thin, delicate, or ring-shaped components.

Why Other Options Are Wrong:

• Eccentric work requires special chucks/fixtures; a simple mandrel does not correct eccentricity.
• Heavy work is often better in a 4-jaw or faceplate with robust support.
• “None of these” is incorrect because thin ring-like jobs are classic mandrel cases.

Common Pitfalls:
Using an undersized mandrel leading to slip; proper interference/expansion and end support between centers are essential for accuracy.

Final Answer:
A thin work