AS 2181.3-1981

1 - AS 2181, PART 3-1981 SCREWING TAPS - INCH SERIES SCREW THREADS
4 - PREFACE
5 - CONTENTS
6 - SECTION 1. SCOPE AND GENERAL
6 - 1.1 SCOPE.
6 - 1.2 TERMS AND DEFINITIONS.
6 - 1.2.1 Terminology of the Thread Profiles.
6 - 1.2.2 General Terminology of Taps.
7 - 1.2.3 Terminology of Cutting Features.
10 - 1.3 MATERIALS.
10 - 1.4 HEAT TREATMENT.
10 - 1.5 MARKING.
11 - SECTION 2. GENERAL DIMENSIONS OF TAPS
11 - 2.1 SCOPE OF SECTION.
11 - 2.2 GENERAL DIMENSIONS OF STANDARD MACHINE AND HAND TAPS.
14 - SECTION 3. SCREW THREAD LIMITS AND TOLERANCES FOR UNIFIED SERIES TAPS
14 - 3.1 SCOPE OF SECTION.
14 - 3.2 GROUND THREAD TAPS.
14 - 3.2.1 Tap Classes.
14 - 3.2.2 Tap Major Diameter.
14 - 3.2.3 Tap Pitch Diameter.
14 - 3.2.4 Tap Minor Diameter.
14 - 3.2.5 Tolerance on Pitch.
14 - 3.2.6 Tolerance on Thread Angle.
14 - 3.2.7 Runout.
14 - 3.3 CUT THREAD TAPS.
14 - 3.3.1 Tap Class.
14 - 3.3.2 Tap Major Diameter.
14 - 3.3.3 Tap Pitch Diameter.
14 - 3.3.4 Tap Minor Diameter.
15 - 3.3.5 Tolerance on Pitch.
15 - 3.3.6 Tolerance on Thread Angle.
15 - 3.3.7 Runout.
26 - SECTION 4. SCREW THREAD LIMITS AND TOLERANCES FOR BSW, BSF AND BA TAPS
26 - 4.1 SCOPE OF SECTION.
26 - 4.2 GROUND THREAD TAPS.
26 - 4.2.1 Tap Classes.
26 - 4.2.2 Tap Major Diameter.
26 - 4.2.3 Tap Pitch Diameter.
26 - 4.2.4 Tap Minor Diameter.
26 - 4.2.5 Tolerance on Pitch.
26 - 4.2.6 Tolerance on Thread Angle.
26 - 4.2.7 Runout.
26 - 4.3 CUT THREAD TAPS.
26 - 4.3.1 Tap Class.
26 - 4.3.2 Tap Major Diameter.
26 - 4.3.3 Tap Pitch Diameter.
26 - 4.3.4 Tap Minor Diameter.
27 - 4.3.5 Tolerance on Pitch.
27 - 4.3.6 Tolerance on Thread Angle.
27 - 4.3.7 Runout.
37 - APPENDIX A - NOTES ON CUMULATIVE PITCH ERROR
38 - APPENDIX B - VALUES OF ELEMENTS FOR USE IN THE BASIC FORMULAS FOR TAPS
43 - APPENDIX C - BASIS OF TOLERANCES FOR MACHINE AND HAND TAP BLANKS
43 - C1 SCOPE.
43 - C2 MANUFACTURING TOLERANCES.
44 - APPENDIX D - SIZES OF INCH SERIES TAP BLANKS
46 - APPENDIX E - DESIGNATION FOR THE PURPOSE OF AN ENQUIRY OR ORDER

Specifies taps for cutting inch series screw threads (including BA). Gives general dimensions, tolerances and deviations for the threaded portion of the tap, materials and properties, and methods of test. Provides for the use of same tap carcass dimensions. Appendices give the imperial dimensions in metric units.

This standard specifies requirements for taps for cutting BA and inch series screw threads. It includes standard machine taps with ground threads, and also taps with cut threads. General dimensions, tolerances and deviations for the threaded portion, types of taps and other main features are specified, but the details of design are left to the manufacturer.NOTE: If specific design features are required these must be specified by the purchaser at the time of his enquiry or order.Taps for tapping of nut threads are not covered in this standard owing to the many varieties in existence.The standard covers screw threads of the following types and size ranges:Unified Coarse Series (UNC) No 1-64 to 4 in-4Unified Fine Series (UNF) No 0-80 to 1 1/2in-12British Standard Whitworth Series (BSW) 1/8in-40 to 4 in-3British Standard Fine Series (BSF) 3/16in-32 to 3 in-5British Association Series (BA) 14 BA-0 BAThe tolerances for the threaded portion of taps are based on those given in previous Australian standards, i.e. the 'zone' tolerance values. To promote a common designation system for all taps the ISO (metric) tap designation system has been introduced for ground thread taps only. Taps with cut threads are designated 'cut thread taps'.

Reconfirmed 1987