vii Contents Chapter 1 Introduction to Dimensioning and Tolerancing . . . . . . . . . . . . . . 1 Technological Developments in Product Documentation. . . . . . . . . . . . . . . . . 2 Design through Teamwork. . . . . . . . . . . . 7 Professions and Trades Affected by Dimensions . . . . . . . . . . . . . . . . . 8 Required Dimensioning Skills . . . . . . . . . . 9 Technical Terminology . . . . . . . . . . . . . 11 Orthographic Projection. . . . . . . . . . . . . 14 Future Trends . . . . . . . . . . . . . . . . . 16 Chapter 2 Dimensioning and Tolerancing Symbology . . . . . . . . . . . . . . . . 21 Associativity in Annotated Models . . . . . . . . 22 General Symbols and Abbreviations . . . . . . . 22 Geometric Tolerancing Symbols . . . . . . . . . 28 Symbols for Castings, Forgings, and Molded Parts . . . . . . . . . . . . . . . . . . . . . 32 Feature Control Frames . . . . . . . . . . . . . 33 Datum Identifi cation . . . . . . . . . . . . . . 36 Basic Dimensions . . . . . . . . . . . . . . . 40 Symbols for Assemblies and Special Applications . . . . . . . . . . . . . . . . . . 41 Past Practices . . . . . . . . . . . . . . . . . 41 Chapter 3 General Dimensioning Requirements . . . . 47 Annotation Planes in Models . . . . . . . . . . 49 Dimensioning Methods . . . . . . . . . . . . . 49 Location and Size Dimensions . . . . . . . . . 50 Line Use. . . . . . . . . . . . . . . . . . . . 51 Character Size and Style . . . . . . . . . . . . 54 Dimension Value Display . . . . . . . . . . . . 54 Scale . . . . . . . . . . . . . . . . . . . . . 56 Measurement Systems . . . . . . . . . . . . . 56 Applicable Tolerances . . . . . . . . . . . . . 59 Dimension Systems. . . . . . . . . . . . . . . 60 Dimension Placement . . . . . . . . . . . . . 65 General Arrangement of Dimensions. . . . . . . 68 Dimensions Applied to Special Views . . . . . . 73 Notes Used in Dimensioning . . . . . . . . . . 75 Types of Fit between Parts . . . . . . . . . . . 78 Geometric Tolerances. . . . . . . . . . . . . . 80 Past Practices . . . . . . . . . . . . . . . . . 81 Chapter 4 Dimension Application and Limits of Size . . . . . . . . . . . . 91 Dimension Application . . . . . . . . . . . . 92 Limits of Size . . . . . . . . . . . . . . . . 121 Calculation of Size Tolerances. . . . . . . . . 122 Rules in ASME Y14.5 . . . . . . . . . . . . 128 Dimensioning for Industry. . . . . . . . . . . 131 Surface Texture Specifi cation . . . . . . . . . 136 Chapter 5 Form Tolerances . . . . . . . . . . . . . 149 Form Tolerance Categories . . . . . . . . . . 150 Feature Control Frames . . . . . . . . . . . . 151 Form Requirements Established by Size Limits . . . . . . . . . . . . . . . . . . . . 153 Straightness . . . . . . . . . . . . . . . . . 156 Flatness . . . . . . . . . . . . . . . . . . . 173 Circularity . . . . . . . . . . . . . . . . . . 179 Cylindricity. . . . . . . . . . . . . . . . . . 183 Form Applied to a Limited Area . . . . . . . . 185 Chapter 6 Datums and Datum Feature References . . 191 Terminology and Applicability . . . . . . . . . 192 Datum Reference Frame . . . . . . . . . . . 195 Datum Feature Identifi cation . . . . . . . . . 197 Establishing Datums and Datum Reference Frames from Datum Features . . . . . . . . . 206 Flat Surfaces as Datum Features . . . . . . . 207 Features of Size as Datum Features . . . . . . 214 Datum Feature References in a Feature Control Frame . . . . . . . . . . . . . . . . 217 Special Applications . . . . . . . . . . . . . 232 Advanced Datum Concepts . . . . . . . . . . 239 Special Datum Applications. . . . . . . . . . 249