Center hole not quite on center?
Ideally, workpieces for lathes and grinders will have center holes drilled exactly in the center, ensuring perfect concentricity. But in the real world of high-paced machining, this is not always the case. Off-center deviations of just a few thousandths will drastically reduce machining accuracy.
Reworking of parts may also cause their center holes to be no longer concentric with the machined surfaces.
Bad center holes are an occasional nuisance, but Riten
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