Modifiers like Maximum Material Condition (MMC) allow for "bonus tolerance" as the part’s actual size deviates from its limit, providing flexibility for manufacturing without sacrificing assembly. Y14.5M-1994 - Dimensioning and Tolerancing - ANSI Webstore
Imaginary, mathematically perfect points, axes, or planes used as reference points for measurements. Dimensioning and Tolerancing ASME Y14.5M-1994
A rectangular box that serves as the primary "sentence" for GD&T. It contains the geometric symbol, the tolerance value, material modifiers (like MMC or LMC ), and datum references. Modifiers like Maximum Material Condition (MMC) allow for
Drawings should define the final part geometry without dictating the specific manufacturing processes (e.g., drilling vs. punching) used to achieve it. Standard Reference Temperature: All dimensions apply at 68∘F68 raised to the composed with power cap F ( 20∘C20 raised to the composed with power cap C ) unless noted otherwise. It contains the geometric symbol, the tolerance value,
The standard relies on several fundamental rules that guide how dimensions and tolerances are applied:
Dimensions and tolerances typically apply when the part is in its "free state" and not being forced or bolted down. Key Components of GD&T in Y14.5M-1994