Contents

Foreword iïi

Standards Committee Roster vii

1 Scope, Definitions, and General Dimensioning I

1.1 General 1

1.2 References 1

1.3 Definitions 2

1.4 Fundamental Rules 4

1.5 Units of Measurement 4

1.6 Types of Dimensioning 5

1.7 Application of Dimensions 6

1.8 Dimensioning Features 10

1.9 Location of Features 18

2 General Toleraneing and Ralatad Principles 7.3

2.1 General 23

2.2 Direct Toleraneing Methods 24

2.3 Tolerance Expression 24

2.4 Interpretation of Limits 25

2.5 Single Limits 25

2.6 Tolerance Accumulation 25

2.7 Limits of Size 26

2.8 Applicability of RFS. MMC, and LMC 28

2.9 Screw Threads 29

2.10 Gears and Splines 29

2.11 Virtual/Resultant Condition 29

2.12 Angular Surfaces 29

2.13 Conical Tapers 29

2.14 Flat Tapers 37

2.15 Radius 38

2.16 Statistical Toleraneing 38

3 Symbology 41

3.1 General 41

3.2 Use of Notes to Supplement Symbols 41

3.3 Symbol Construction 41

3.4 Geometric Tolerance Symbols 47

3.5 Feature Control Frame Placement 48

3.6 Definition of the Tolerance Zone 48

3.7 Tabulated Tolerances 50

4 Datum Referencing 51

4.1 General 51

4.2 Immobilization of Pait 51

4.3 Datum Features 52

4.4 Specifying Datum Features in an Order of Precedence 52

4.5 Establishing Datums 55

4.6 Datum Targets 70

5 Tolerances of Locetion 81

5.1 General 81

5.2 Positional Tolerancing 81

5.3 Fundamental Explanation of Positional Tolerancing 81

5.4 Feature Pattern Location 93

5.5 Projected Tolerance Zone 115

5.6 Nonparaliel Holes 135

5.7 Counterbored Holes 135

5.8 Closer Control at One End of a Feature 135

5.9 Bidirectional Positional Tolerancing of Features 135

5.10 Noncircular Features 139

5.11 Coaxiality Controls 142

5.12 Concentricity 144

5.13 Positional Tolerancing for Symmetrical Relationships 149

5.14 Symmetry Tolerancing to Control the Median Points of Opposed or Correspondingly-Located Elements of Features 149

5.15 Spherical Features 149

6 Tolerances of Form, Profile, Orientation, and Runout 157

6.1 General 157

6.2 Form and Orientation Control 157

6.3 Specifying Form and Orientation Tolerances 157

6.4 Form Tolerances 157

6.5 Profile Control 163

6.6 Orientation Tolerances 174

6.7 Runout 189

6.8 Free State Variation 191

Appendices

A Principal Changes and Improvements 197

A1 General 197

A2 Figures 197

A3 Section 1, Scope, Definitions, and General Dimensioning 197

A4 Section 2. General Tolerancing and Related Principles 198

A5 Section 3, Symbology 199

A6 Section 4, Datum Referencing 199

A7 Section 5, Tolerances of Location 200

A8 Section 6, Tolerances of Form, Profile, Orientation, and Runout 202

A9 Appendix A, Principal Changes and Improvements 202

A10 Appendix B, Formulas for Positional Tolerancing 203

A11 Appendix C, Form, Proportion, and Comparison of Symbols 203

A12 Appendix D, Former Practices 203

A13 Appendix E, Decision Diagrams for Geometric Control 203

B Formulas for Positional Tolarandng 205

B1 General 205

B2 Formula Symbols 205

B3 Floating Fastener Case 205

B4 Fixed Fastener Case When Projected Tolerance Zone Is Used 205

B5 provision for Out-of-Squareness When Projected Tolerance Zone is

Not Used 206

B6 Coaxial Features 207

B7 Limits and Fits 207

C Form, Proportion, and Comparison of Symbols 209

CI General 209

C2 Form and Proportion 209

C3 Comparison 209

D Formsr Practices 215

D1 General 215

D2 Definition for Feature of Size 215

D3 Applicability of RFS. MMC, and LMC 215

D4 Tangent Radii 215

D5 Datum Feature Symbol 215

D6 Projected Tolerance Zone 215

E Decision Diagrams for Geometric Control 219

El Purpose 219

E2 Functional Requirements 219

E3 Reference to Standard 219

E4 Geometric Controls 219

E5 Choosing Other Controls 219

E6 Use of Modifiers 219

E7 Datums 219

Index 229

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