Unit 15 Geometric Dimensioning and Tolerancing 267 Copyright Goodheart-Willcox Co., Inc. Example If a .010″ position tolerance is specified for a .750/.752″ hole at LMC, Figure 15‑15, the tolerance zone would increase to .011″ for a .751″ hole and .012″ for a .750″ hole. The change in tolerance is equal to the change in hole diameter. Regardless of Feature Size Regardless of feature size (RFS) is the condition at which the specified tolerance remains the same and does not change regardless of the actual size of the feature. Example If a .010″ position tolerance is specified for a .750/.752″ hole, the tolerance zone remains the same, Figure 15‑16, regardless of whether the hole is .750″, .751″, or .752″ in diameter. A tolerance specified at RFS applies independent of feature size. Additional Modifying Symbols Other modifying symbols used in the GD&T system include the projected tolerance zone symbol, the tan- gent plane symbol, and the free state symbol. Refer to Figure 15‑12. The projected tolerance zone symbol is used to indicate that the tolerance zone is to be projected outside the controlled feature. The projected tolerance zone symbol is an encircled P. The tangent plane symbol indicates that the specified tolerance is to apply to a tangent plane. The tangent plane symbol is an encir- cled T. The free state symbol indicates that the specified Drawing Interpretation Goodheart-Willcox Publisher Figure 15-14. When a tolerance specification includes the MMC modifier, the specified tolerance value applies when the feature is at MMC. At different allowable hole sizes, the tolerance increases as the hole size varies from MMC. The position tolerance specification on the drawing shown includes the MMC modifier. The diameter symbol (Ø) in front of the tolerance value indicates that the tolerance zone is cylindrical. When the feature is at MMC, the tolerance is .010. When the feature is produced at a size of .752, the tolerance increases to .012. The axis of the hole must be located in the tolerance zone.