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BS 93:2008 British Association (B.A.) screw threads. Requirements, 2008
- Contents [Go to Page]
- 1 Scope 1
- 2 Normative references 1
- 3 Terms and definitions and symbols 1
- 4 Profile of British Association (B.A.) screw thread 2
- 5 Basic sizes of B.A. threads 3
- 6 Tolerance classes and limits of sizes, and tolerances, for B.A. threads 3
- 7 Gauges 4
- Annexes
- Annex A (informative) Basis of sizes of B.A. threads 12
- Annex B (informative) Bases of allowances and tolerances for B.A. threads 12
- Annex C (informative) Effect of errors in pitch and flank angle on the effective diameter 14
- Annex D (informative) Approximate inch equivalents of B.A. thread sizes 16
- Bibliography 21
- List of figures
- Figure 1 - Basic form of B.A. thread 2
- Figure 2 - Tolerance zones for a close class external thread and an internal thread 5
- Figure 3 - Tolerance zones for a normal class external thread and an internal thread 5
- Figure 4 - Example of effective diameter tolerance zones (Effective diameter tolerance zones for size 2 B.A. threads illustrated) 6
- List of tables
- Table 1 - Basic sizes of British Association (B.A.) screw threads 7
- Table 2 - Limits and tolerances for close class external threads - Sizes 0 B.A. to 10 B.A. 8
- Table 3 - Limits and tolerances for normal class external threads - Sizes 0 B.A. to 10 B.A. 9
- Table 4 - Limits and tolerances for normal class external threads - Sizes 11 B.A. to 16 B.A. 10
- Table 5 - Limits and tolerances for internal threads - Sizes 0 B.A. to 16 B.A. 11
- Table B.1 - Summary of tolerance formulae 13
- Table D.1 - Basic sizes of British Association (B.A.) screw threads - Approximate inch equivalents 16
- Table D.2 - Limits and tolerances for close class external threads - Sizes 0 B.A. to 10 B.A. - Approximate inch equivalents 17
- Table D.3 - Limits and tolerances for normal class external threads - Sizes 0 B.A. to 10 B.A. - Approximate inch equivalents 18
- Table D.4 - Limits and tolerances for normal class external threads - Sizes 11 B.A. to 16 B.A. - Approximate inch equivalents 19
- Table D.5 - Limits and tolerances for internal threads - Sizes 0 B.A. to 16 B.A. - Approximate inch equivalents 20
- Foreword
- 1 Scope [Go to Page]
- a) basic sizes for B.A. threads, sizes 0 B.A. to 16 B.A.;
- b) limits of size, and tolerances, for close class and normal class external threads of sizes 0 B.A. to 10 B.A.;
- c) limits of size, and tolerances, for normal class external threads of sizes 11 B.A. to 16 B.A.;
- d) limits of size, and tolerances, for a single class of internal threads of sizes 0 B.A. to 16 B.A.
- 2 Normative references
- 3 Terms and definitions and symbols [Go to Page]
- 3.1 Terms and definitions
- 3.2 Symbols
- 4 Profile of British Association (B.A.) screw thread [Go to Page]
- Figure 1 Basic form of B.A. thread
- 5 Basic sizes of B.A. threads
- 6 Tolerance classes and limits of sizes, and tolerances, for B.A. threads [Go to Page]
- a) Close class external threads. Limits and tolerances for close class external threads of sizes 0 B.A. to 10 B.A. shall be as specified in Table 2.
- b) Normal class external threads. Limits and tolerances for normal class external threads of sizes 0 B.A. to 10 B.A. shall be as...
- 7 Gauges [Go to Page]
- Figure 2 Tolerance zones for a close class external thread and an internal thread
- Figure 3 Tolerance zones for a normal class external thread and an internal thread
- Figure 4 Example of effective diameter tolerance zones (Effective diameter tolerance zones for size 2 B.A. threads illustrated) [Go to Page]
- Table 1 Basic sizes of British Association (B.A.) screw threads
- Table 2 Limits and tolerances for close class external threads - Sizes 0 B.A. to 10 B.A.
- Table 3 Limits and tolerances for normal class external threads - Sizes 0 B.A. to 10 B.A.
- Table 4 Limits and tolerances for normal class external threads - Sizes 11 B.A. to 16 B.A.
- Table 5 Limits and tolerances for internal threads - Sizes 0 B.A. to 16 B.A.
- Annex A (informative) Basis of sizes of B.A. threads
- Annex B (informative) Bases of allowances and tolerances for B.A. threads [Go to Page]
- B.1 Allowances
- B.2 Tolerances
- B.3 Tolerances on effective diameters [Go to Page]
- B.3.1 External threads
- B.3.2 Internal threads
- B.4 Tolerances on major diameters [Go to Page]
- B.4.1 External threads
- B.4.2 Internal threads
- B.5 Tolerances on minor diameters [Go to Page]
- B.5.1 External threads
- B.5.2 Internal threads [Go to Page]
- Table B.1 Summary of tolerance formulae
- Annex C (informative) Effect of errors in pitch and flank angle on the effective diameter [Go to Page]
- C.1 Effect of pitch errors
- C.2 Effect of errors in flank angle
- C.3 Criteria for acceptability of a combination of errors in the effective diameter, pitch and flank angle of a screw thread [Go to Page]
- a) External threads. To be acceptable, the simple effective diameter of an external thread (as measured along the pitch line of ...
- b) Internal threads. To be acceptable, the simple effective diameter of an internal thread (as measured along the pitch line of ...
- Annex D (informative) Approximate inch equivalents of B.A. thread sizes [Go to Page]
- Table D.1 Basic sizes of British Association (B.A.) screw threads - Approximate inch equivalents
- Table D.2 Limits and tolerances for close class external threads - Sizes 0 B.A. to 10 B.A. - Approximate inch equivalents
- Table D.3 Limits and tolerances for normal class external threads - Sizes 0 B.A. to 10 B.A. - Approximate inch equivalents
- Table D.4 Limits and tolerances for normal class external threads - Sizes 11 B.A. to 16 B.A. - Approximate inch equivalents
- Table D.5 Limits and tolerances for internal threads - Sizes 0 B.A. to 16 B.A. - Approximate inch equivalents
- Bibliography [Go to Page]