What method is used to inspect the smoothness of holes after deburring?

The method of using your forefinger and thumb to inspect the smoothness of holes after deburring is effective because it allows the inspector to feel for any irregularities or rough edges that may not be visible to the naked eye. This tactile feedback is valuable in evaluating the finish of the hole, as the sensitivity of the fingertips can detect variations in texture and smoothness.

Directly feeling the surface with your fingers can reveal imperfections that could impact the fit or function of components that will interface with the deburred hole. This technique is often employed when tactile sensitivity is more informative than visual assessment, especially in cases where visual cues alone may not provide a complete understanding of the surface condition.

Other methods, while useful in specific contexts, may not be as effective for this particular purpose. For instance, using a microscope is primarily beneficial for inspecting very fine details or microscopic imperfections but may not be practical for the general assessment of surface smoothness in larger holes. Visual inspection relies heavily on sight and can sometimes miss subtle variations in texture that can be felt, while measuring calipers provide quantitative measurements rather than qualitative assessments of smoothness.