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A circled M allowing extra tolerance as a feature shrinks.
Also known as: MMC modifier, Circled M, Bonus tolerance symbol
A circled M after a tolerance value says the stated tolerance applies at the feature's maximum material condition, and grows as the feature departs from it. It is the modifier that makes geometric tolerancing cheaper to satisfy, and it applies only where function permits.
States that the tolerance applies when the feature contains the most material, with bonus tolerance available as it departs from that condition.
Contexts: Technical drawing
Is appropriate only where the feature's function is assembly clearance, since bonus tolerance would be wrong on a feature whose fit is critical.
Contexts: Technical drawing
A capital letter M enclosed in a circle, set after a numeral inside a rectangular frame.