Technical Committee on Technical Drawings
Preface
1 Scope
2 Reference Publications
3 Definitions of Terms
4 Fundamental Rules
4.1 General
4.2 Four Aspects of Each Feature
4.3 Implied Geometric Form
4.4 Relationship Between Requirements
4.5 Specification of Values for Dimensions and
Tolerances
4.6 Indicating Manufacturing Operations
4.7 Free State and Orientation
4.8 Rules for Geometrical Tolerancing
5 Symbology
5.1 General
5.2 Use of Notes to Supplement Symbols
5.3 Symbol Construction
6 Elements of Dimensioning
6.1 Scope
6.2 Application
6.3 Dimensioning Units
6.4 Line Conventions
6.5 Extension (Projection) Lines
6.6 Dimension Lines
6.7 Centre Lines
6.8 Dimension Line Termination
6.9 Leaders
6.10 Placement of Values
6.11 Basic (Exact) Dimensions
6.12 Not to Scale
6.13 Choice of Dimensions
7 Dimensioning Common Features
7.1 Diameters
7.2 Radii
7.3 Rounded Ends and Slotted Holes
7.4 Counterbored and Spot-Faced Holes
7.5 Countersunk and Counterdrilled Holes
7.6 Chords, Arcs and Angles
7.7 Profiles
7.8 Symmetrical Outlines
7.9 Square Features
7.10 Machining Centres
7.11 Chamfers
7.12 Slopes
7.13 Tapers
7.14 Keyseats
7.15 Knurls
7.16 Undercuts
7.17 Rod and Tube Detail
7.18 ISO Metric Screw Threads
7.19 Pipe Threads
7.20 Surface Texture
7.21 Gears and Splines
7.22 Castings
7.23 Forgings
8 Location of Features
8.1 General
8.2 Rectangular Co-ordinates
8.3 Polar Co-ordinates
8.4 Point-to-Point Dimensioning
8.5 Common-Point Dimensioning
8.6 Arrowless Dimensioning
8.7 Tabular Dimensioning
8.8 Repetitive Features and Dimensions
8.9 Other Dimensioning Methods
9 Datums
9.1 General
9.2 Three-Plane Datum System
9.3 Selection of Manufacturing Datum Features
9.4 Identification of Datum Features
9.5 Datum Targets
9.6 Datum Features
9.7 Datums on a Maximum Material Condition (MMC) Basis
9.8 Combining the Datum Feature Indicator with a
Dimension Line
10 General Tolerancing and Related Principles
10.1 General
10.2 Direct Tolerancing Methods
10.3 Tolerance Expressions
10.4 Indication of Fits and Tolerances on Drawings
Assembled Parts
10.5 General Tolerance Notes
10.6 Interpretation of Tolerances
10.7 Effect of Surface Coatings
10.8 Tolerance Accumulation
10.9 Limits of Size
10.10 Screw Threads
10.11 Gears and Splines
10.12 Sloped Surfaces
10.13 Tapers
10.14 Tangent Radii
11 Geometrical Tolerancing
11.1 General
11.2 Geometrical Characteristics
11.3 Relationship to Feature Size - Regardless of
Feature Size (RFS)
11.4 Relationship to Feature Size - Maximum Material
Condition (MMC)
11.5 Tolerance Notes and Symbols
11.6 Application of Symbols to Drawings
11.7 Application of Symbols with Datum Systems
11.8 Interdependence of Geometrical Tolerances
12 Tolerances of Location
12.1 General
12.2 Direct Tolerancing
12.3 Positional Tolerancing
12.4 Location of Groups of Features
12.5 Feature Pattern Location - Composite Positional
Tolerancing
12.6 Projected Tolerance Zone
12.7 Counterbored Holes
12.8 Closer Control at One End of a Feature
12.9 Control in Two Directions
12.10 Noncylindrical Features
12.11 Coaxiality Controls
12.12 Symmetry
12.13 Spherical Features
13 Tolerances of Form, Orientation, Profile and Runout
13.1 General
13.2 Form and Orientation Tolerances
13.3 Profile Tolerances
13.4 Runout Tolerance
13.5 Free State Variation
14 Dimensioning of Casting Drawings
14.1 General
14.2 Casting Datums
14.3 Machining Datums
14.4 Dimensions
14.5 Draft
14.6 Cored Holes for Threads
14.7 Fillets and Radii
14.8 Machining Allowances
15 Dimensioning for Computer-Aided Design and Computer-
Aided Manufacturing Mode
15.1 General
15.2 Co-ordinate System
15.3 Reference Planes
15.4 Reference Axes
15.5 Mathematical Quadrants
15.6 Dimensioning and Tolerancing
15.7 Incorporating Dimensional Changes
16 Formulas for Positional Tolerancing
16.1 General
16.2 Formula Symbols
16.3 Floating Fastener Case
16.4 Fixed Fastener Case
16.5 Coaxial Features
16.6 Perpendicularity Errors
17 Form, Proportion and Comparison of Symbols
17.1 General
17.2 Form and Proportion
17.3 Comparison
Appendices
A Information on Obtaining Publications Referred to
in this Standard
B Bibliography of International Standards
C Variances in Drawing Practice Standards