Least Material Condition (LMC) is a GD&T symbol indicating the maximum or minimum allowed tolerance of a feature where it has the smallest amount of material (volume/size).
- In a hole/bore, LMC = Maximum allowed diameter according to the tolerance.
- In a Shaft/pin, LMC = Minimum allowed diameter according to the tolerance.
LMC is used to control areas with thin walls or risk of low strength, for example, a bore near the edge of a plate. In such a case, combining a hole having a larger diameter with an outer position can cause a fragile wall or even a breach. LMC is also useful for designing parts with strict space requirements.
