12 Geometric Dimensioning and Tolerancing Copyright Goodheart-Willcox Co., Inc. Geometric tolerancing specifies functional requirements more precisely than coordinate tolerancing, leaving no doubt as to the intended definition. Use of the word precise in this context does not imply tighter tolerances. The use of precise means a more exact definition of the features with no doubt about the meaning. This level of precision is not achieved when using coordinate tolerancing. For a number of reasons, coordinate tolerancing is not as pre- cise as geometric tolerancing. Similar limitations exist when notes are used on a drawing or model to define tolerances. Notes defining tolerances can be unclear or can be interpreted differently by someone using the drawing or model, depending on how they are written. The limitations of coordinate tolerancing, and the advantages of GD&T, are associ- ated with several factors. These factors include the following: • Coordinate systems • Dimension and tolerance origin • Tolerance zones • Tolerance buildup N O T E The following sections introduce a variety of fundamental GD&T concepts, symbols, and terminology. You will learn more about these topics through- out this textbook. Drafting, design, and training for all disciplines. ENGINEERING DRAFTING & DESIGN, INC. Integrity - Quality - Style Goodheart-Willcox Publisher Example 1-7. The face plate from Example 1-5 defined using GD&T.