Measure Normal to the Surface (#151)
(In accordance with Y14.5M-1994 standard)
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When measuring nearly every geometric control, the indicator or CMM probe should move normal (at 90°) to the surface. The exception is circularity when applied to a conical surface. Circularity requires that the movement be in a plane normal to the axis rather than the surface. If the movement for other geometric controls is not normal to the …
