Remember that Size Controls Form
Below is a redraw of a print that was sent to me by a supplier who wanted to quote on the job but was concerned that he did not have any equipment that could measure the cylindricity callout. I pointed out that by correctly inspecting the size of the 40mm hole according to Rule #1 of the Y14.5 standard, the form (straightness, circularity and cylindricity) of the hole would all have to be within 0.04. In other words, the hole must accept a full form go-gage not smaller than 39.98 and the actual local size at each cross section must not exceed 40.02. The cylindricity requirement in this case is redundant given the size tolerance.
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