266 Machine Trades Print Reading Copyright Goodheart-Willcox Co., Inc. Example MMC of a Ø.750/.752″ shaft is .752″ MMC of a Ø.750/.752″ hole is .750″ When a tolerance is specified at MMC, the allowable tolerance is determined by the feature size. If the actual feature size has varied from MMC, an increase in the tolerance equal to that amount of variance is allowed. Example If a .010″ position tolerance is specified for a .750/.752″ hole at MMC, Figure 15‑14, the tolerance zone would increase to .011″ for a .751″ hole and .012″ for a .752″ hole. Tolerance increases are equal to the amount of change in hole diameter. Least Material Condition Least material condition (LMC) is the condition of a feature that is at the size limit resulting in the least amount of material on the part. LMC means that an external feature, such as a shaft, is at the low size limit (minimum size) and that an internal feature, such as a hole or slot, is at the high size limit (maximum size). Example LMC of a Ø.750/.752 shaft is .750″ LMC of a Ø.750/.752 hole is .752″ When a tolerance is specified at LMC, the allowable tolerance is determined by the feature size. If the actual feature size has varied from LMC, an increase in the tolerance equal to that amount of variance is allowed. GD&T Symbols Maximum material condition Maximum material boundary Least material condition Least material boundary Regardless of feature size Projected tolerance zone Tangent plane Free state Statistical tolerance Between ASME Y14.5 None Discontinued Regardless of material boundary None Goodheart-Willcox Publisher Figure 15-12. Material condition and material boundary modifier symbols and other GD&T symbols. Goodheart-Willcox Publisher Figure 15-13. A material condition modifier symbol following the tolerance in the feature control frame indicates the appli- cable material condition.