164 Chapter 7
7.2 illustrates a typical method used to show tolerances for holes and shafts. Surfaces being toleranced
have geometrical characteristics such as roundness or perpendicularity to another surface. Figure 7.3
demonstrates typical symbols used in lieu of or in conjunction with notes to state the geometric charac-
teristics being toleranced.
Figure 7.1 Three methods of indicating tolerances: A. Unilateral method, B. Bilateral method, and C. Limit
dimensioning method (source: Blueprint Reading and Sketching, Navedtra 14040).