Improving surface finish in turning Which changes generally improve surface finish, assuming stable setup and appropriate tool material?

Introduction / Context:
Surface finish results from the interplay of tool geometry, cutting parameters, machine stiffness, and material behavior. Certain parameter changes consistently reduce feed marks and improve the machined texture when other conditions are controlled.

Given Data / Assumptions:

• Stable workholding and machine condition (no chatter).
• Proper tool material for the workpiece.
• Reasonable feeds and depths for finishing.

Concept / Approach:
Higher cutting speed often improves finish by reducing built-up edge. A larger tool nose radius blends feed marks, producing a smoother surface, though it may increase cutting forces. A more positive rake promotes shearing over ploughing, reducing forces and improving flow of chips.

Step-by-Step Solution:

Verification / Alternative check:
Surface-roughness models relate cusp height to feed and nose radius; tribological data tie built-up edge to speed and rake.

Why Other Options Are Wrong:
Choosing any single factor ignores the combined benefit. The distractor advocating lower speed and negative rake typically worsens finish due to BUE and rubbing.

Common Pitfalls:
Excessive nose radius on a flexible setup can induce chatter; always balance geometry with machine rigidity and feed.

Final Answer:

All of these