v New to This Edition The seventh edition of GD&T: Application and Interpretation explains required practices in the ASME Y14.5-2018 standard and other applicable standards. This text has been revised to cover current dimensioning and tolerancing practices, applica- tions in industry, and technological developments. Practices related to annotated models are empha- sized throughout this edition. Practices related to orthographic views are also shown. Where practices are signifi cantly different between annotated models and orthographic views, both practices are explained. Throughout the text, technical explanations have been expanded and clarifi ed to make process steps easier to follow. Figures have been added to illustrate the differences between similar terms, such as “axis” and “derived median line.” Practices explained in this edition are based on common industry practices and applicable stan- dards. When an explanation of a past practice is given, the practice is called out as a “past practice.” Where suitable, reference is made to the applicable previous version of the standard. Standard practices in this text are based on the following standards. ■ ANSI B4.2-1978 Preferred Metric Limits and Fits ■ ASME Y14.2-2014 Line Conventions and Lettering ■ ASME Y14.3-2012 Orthographic and Pictorial Views ■ ASME Y14.5-2018 Dimensioning and Tolerancing ■ ASME Y14.5.1M-1994 Mathematical Defi nition of Dimensioning and Tolerancing Principles ■ ASME Y14.8-2009 Castings, Forgings, and Molded Parts ■ ASME Y14.36M-1996 Surface Texture Symbols ■ ASME Y14.41-2012 Digital Product Defi nition Data Practices ■ USASI B4.1-1967 Preferred Limits and Fits for Cylindrical Parts This edition includes coverage of advances based on changes to these standards. Examples and new topics have been added, or content has been expanded, for the following. ■ Profi le tolerance application for location of surfaces is emphasized. ■ Defi nitions have been updated to align with those added or revised in ASME Y14.5. ■ Explanations have been revised for application of the free state symbol and restrained part condition. ■ The text explains that “as-designed” dimensions (sometimes called “nominal”) do not default to establish a manufacturing target. ■ Rule #1 is now applicable to localized areas without opposed points. ■ Applications of symbols in models are shown and limitations are given for some symbols in orthographic views. ■ Symbols are shown and explained for the following. ■ Dynamic profi le symbol ■ From–to symbol ■ Symbols related to parting lines ■ Aggregate datum feature symbol ■ Elliptical fi llet and parabolic fi llet symbols ■ The text explains that the concentricity and symmetry tolerance symbols are not included in the ASME Y14.5-2018 standard. Other methods of achieving coaxial and symmetrical relationships are explained. ■ Effects of straightness tolerances on datum feature simulation are explained. ■ Explanations have been expanded for simulation of surfaces referenced tertiary at MMB or LMB. ■ The term common datum feature has replaced multiple datum feature. ■ Orientation of radial elements is controlled with line profi le tolerances. Orientation tolerances are no longer used for this purpose. ■ Position tolerances applied at MMC are explained in terms of the surface method and the axis method. ■ Unequally disposed profi le tolerances are no longer indicated using phantom lines. ■ Coverage has been added to explain application of a dynamic profi le tolerance. ■ The text explains application of a runout tolerance to a tangent plane. ■ The text explains application of a runout tolerance relative to an axis of rotation in an assembly.