Maximum material condition

In practice

MMC callouts suit clearance fits such as bolt holes, and they allow functional gauging. Least material condition (LMC) is the opposite state.

Related terms

True position

True position is a GD&T location control that defines a tolerance zone, usually cylindrical, around the theoretically exact location of a feature such as a hole, relative to datums. A diameter-zone position callout gives about 57% more tolerance area than the equivalent plus-minus square zone.

GD&T

GD&T is geometric dimensioning and tolerancing, the symbol system defined in ASME Y14.5 and ISO 1101 for controlling the form, orientation, location, and runout of part features relative to datums. It states functional intent more precisely than plus-minus dimensions and often allows larger tolerances where they do not matter.

Tolerance

Tolerance is the total amount a dimension is allowed to vary from its nominal value, such as ±0.005 in (±0.13 mm). Tighter tolerances raise cost through slower processes, extra operations, and added inspection. Hold them only on features that affect fit or function.