Which of the following best describes the effect of pinch back in a cutting operation?

The effect of pinch back in a cutting operation is best described by the narrowing of the cut width. Pinch back occurs when the material being machined is forced against the cutting edge of the tool, typically during the retraction or non-cutting phase of the tool movement. This force can compress the material slightly, leading to a reduction in the effective width of the cut being made.

This phenomenon can be particularly notable in operations involving high feed rates or heavy cuts, where the tool’s geometry and cutting conditions contribute to the material "pinching" against the tool. The result is a narrower cut compared to what is intended or programmed, which can influence the overall precision and quality of the machining process. Understanding pinch back is essential in optimizing cutting conditions to achieve desired dimensional accuracy and surface finish.