2.7.1 Where only a tolerance of size is specified, the limits of size of an individual feature prescribe the extent of which variations in its geometric form, as well as size, are allowed.
2.7.1.1 The actual local size of an individual feature at each cross section shall be within the specified tolerance of size.
Here it is from the 94 standard.
2.7.1.2 (a) The surface or surfaces of a feature shall not extend beyond a boundary (envelope) of perfect form at MMC. This boundary is the true geometric form represented by the drawing. No variation is permitted if the feature is produced at its MMC limit of size.
(b) Where the actual local size of a feature has departed from MMC toward LMC, a variation in form is allowed equal to the amount of such departure.
(c) There is no requirement for a boundary of perform form at LMC. Thus, a feature produced at its LMC limit of size is permitted to vary from true form to the maximum variation allowed by the boundary of perform form at MMC.
