Centreless grinding application: The grinding of long, slender shafts or bars is most commonly performed by which method?

Introduction / Context:
Centreless grinding offers three principal modes: infeed (plunge), through-feed, and end-feed. Selecting the correct mode is dictated by part geometry and production volume. Long, slender parts present unique handling and stability challenges.

Given Data / Assumptions:

• Workpieces are long and relatively flexible (high slenderness ratio).
• Need continuous support and steady material flow.
• Tight tolerances on diameter and roundness are desired.

Concept / Approach:
Through-feed centreless grinding feeds the part axially between the wheels while it is supported on a work rest blade. The regulating wheel controls rotation and axial feed. This method provides excellent support along the length, minimizes deflection, and enables very high productivity for uniform cylindrical sections such as bars and shafts.

Step-by-Step Solution:

Verification / Alternative check:
Infeed mode is preferred for shoulders, profiles, or plunge features, not for long uniform shafts. End-feed suits tapered parts or parts with a defined axial stop, less ideal for long bars.

Why Other Options Are Wrong:

• Infeed: limited axial motion; suited to short parts or features.
• End-feed: used for tapers/steps; not optimal for uniform long bars.
• “Any of the above”: ignores the practical advantages of through-feed for slender bars.

Common Pitfalls:
Poor support or incorrect above-centre height can cause chatter or lobing. Use guides and supports for very long bars to avoid whip.

Final Answer:
Through-feed centreless grinding