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BS 84:2007 Parallel screw threads of Whitworth form. Requirements, 2007
- Contents [Go to Page]
- 1 Scope 1
- 2 Normative references 1
- 3 Terms and definitions and symbols 1
- 4 Profile of Whitworth screw thread 2
- 5 Tolerance classes of external and internal threads 3
- 6 Limits of sizes, and tolerances, for uncoated B.S.W. and B.S.F. threads 3
- 7 Limits of size, and tolerances, for B.S.W. and B.S.F. coated threads 4
- 8 Stainless steel external threads 5
- 9 Selected thread series 6
- 10 Designation of screw threads of Whitworth form 8
- 11 Gauges 8
- Annexes
- Annex A (normative) Truncated Whitworth form threads with flat crests 40
- Annex B (informative) Bases of tolerances and allowances for Whitworth form screw threads 47
- Annex C (informative) Tolerances on pitch and flank angle in relation to tolerance on effective diameter 50
- Annex D (informative) Form of the crests of Whitworth threads 53
- Annex E (normative) Limits and tolerances for close class internal threads for special uses 55
- List of figures
- Figure 1 - Basic form of Whitworth thread 9
- Figure 2 - Effective diameter tolerance zones of recommended combinations of classes of internal and external Whitworth form threads 10
- Figure 3 - Tolerance zones for a close class external thread and a medium class internal thread [ in B.S.W. (20 t.p.i.) illustrated] 11
- Figure 4 - Tolerance zones for a medium class external thread with allowance and a normal class internal thread [ in B.S.W. (20 t.p.i.) illustrated] 12
- Figure 5 - Tolerance zones for a free class external thread with allowance and a normal class internal thread [ in B.S.W. (20 t.p.i.) illustrated] 13
- Figure 6 - Effective diameter tolerance zones for external and internal threads, uncoated or before coating, and after coating (c.f. Figure 2) of sizes in nominal size and smaller 14
- Figure A.1 - Tolerance zones for truncated Whitworth threads (close class external thread and medium class internal thread) [ in B.S.W. (20 t.p.i.) illustrated] 43
- Figure D.1 - Crest forms resulting from different production methods 54
- List of tables
- Table 1 - Coarse thread series (B.S.W.) - Basic sizes 15
- Table 2 - Coarse thread series (B.S.W.) - External threads - Close class - Limits and tolerances 16
- Table 3 - Coarse thread series (B.S.W.) - Internal threads - Medium class - Limits and tolerances 17
- Table 4 - Coarse thread series (B.S.W.) - External threads - Medium class - Limits and tolerances 18
- Table 5 - Coarse thread series (B.S.W.) - Internal threads - Normal class - Limits and tolerances 19
- Table 6 - Coarse thread series (B.S.W.) - External threads - Free class - Limits and tolerances 20
- Table 7 - Fine thread series (B.S.F.) - Basic sizes 21
- Table 8 - Fine thread series (B.S.F.) - External threads - Close class - Limits and tolerances 22
- Table 9 - Fine thread series (B.S.F.) - Internal threads - Medium class - Limits and tolerances 23
- Table 10 - Fine thread series (B.S.F.) - External threads - Medium class - Limits and tolerances 24
- Table 11 - Fine thread series (B.S.F.) - Internal threads - Normal class - Limits and tolerances 25
- Table 12 - Fine thread series (B.S.F.) - External threads - Free class - Limits and tolerances 26
- Table 13A - Selected thread series (Whit. S.) - Preferred diameters and pitches - Fractional sizes 27
- Table 13B - Selected thread series (Whit. S.) - Preferred diameters and pitches - Decimal sizes 31
- Table 14 - Selected thread series (Whit. S.) and non-standard threads - Depths of thread for various pitches 34
- Table 15 - Selected thread series (Whit. S.) and non-standard threads - External threads - Medium and free class - Allowances 37
- Table 16 - Selected thread series (Whit. S.) and non-standard threads - External threads - Close class - Tolerances 37
- Table 17 - Selected thread series (Whit. S.) and non-standard threads - Internal threads - Medium class - Tolerances 38
- Table 18 - Selected thread series (Whit. S.) and non-standard threads - External threads - Medium class - Tolerances 38
- Table 19 - Selected thread series (Whit. S.) and non-standard threads - Internal threads - Normal class - Tolerances 39
- Table 20 - Selected thread series (Whit. S.) and non-standard threads - External threads - Free class - Tolerances 39
- Table A.1 - Truncated threads - Whitworth form - Basic data 44
- Table A.2 - Truncated threads - British Standard Whitworth (B.S.W.) series - External and internal threads - All classes - Limits and tolerances 45
- Table A.3 - Truncated threads - British Standard Fine (B.S.F.) series - External and internal threads - All classes - Limits and tolerances 46
- Table E.1 - Coarse thread series (B.S.W.) - Internal threads - Close class - Limits and tolerances 55
- Table E.2 - Fine thread series (B.S.F.) - Internal threads - Close class - Limits and tolerances 56
- Table E.3 - Selected and non-standard threads - Internal threads - Close class - Tolerances 57
- Foreword
- 1 Scope [Go to Page]
- a) a coarse thread series, the British Standard Whitworth (B.S.W.) series, with nominal diameters in the range in to 6 in.
- b) a fine thread series, the British Standard fine (B.S.F.) series, with nominal diameters in the range in to 4 in.
- c) a supplementary selected thread (WHIT. S.) series with nominal diameters from in to 7 in.
- d) a truncated Whitworth form series (specified in Annex A).
- 2 Normative references
- 3 Terms and definitions and symbols [Go to Page]
- 3.1 Terms and definitions
- 3.2 Symbols
- 4 Profile of Whitworth screw thread
- 5 Tolerance classes of external and internal threads [Go to Page]
- a) close class external threads;
- b) medium class external threads and internal threads;
- c) free class external threads;
- d) normal class internal threads.
- 6 Limits of sizes, and tolerances, for uncoated B.S.W. and B.S.F. threads
- 7 Limits of size, and tolerances, for B.S.W. and B.S.F. coated threads
- 8 Stainless steel external threads
- 9 Selected thread series [Go to Page]
- 9.1 General
- 9.2 Basic sizes
- 9.3 Design sizes [Go to Page]
- 9.3.1 Internal threads
- 9.3.2 External threads [Go to Page]
- a) Close class. The design sizes shall be the same as the basic sizes.
- b) Medium class and free class: [Go to Page]
- 2) Basic major diameters above in. The design sizes shall be the same as the basic sizes.
- 9.4 Tolerances
- 10 Designation of screw threads of Whitworth form
- 11 Gauges [Go to Page]
- Figure 1 Basic form of Whitworth thread
- Figure 2 Effective diameter tolerance zones of recommended combinations of classes of internal and external Whitworth form threads
- Figure 3 Tolerance zones for a close class external thread and a medium class internal thread [ in B.S.W. (20 t.p.i.) illustrated]
- Figure 4 Tolerance zones for a medium class external thread with allowance and a normal class internal thread [ in B.S.W. (20 t.p.i.) illustrated]
- Figure 5 Tolerance zones for a free class external thread with allowance and a normal class internal thread [ in B.S.W. (20 t.p.i.) illustrated]
- Figure 6 Effective diameter tolerance zones for external and internal threads, uncoated or before coating, and after coating (c.f. Figure 2) of sizes in nominal size and smaller [Go to Page]
- Table 1 Coarse thread series (B.S.W.) - Basic sizes
- Table 2 Coarse thread series (B.S.W.) - External threads - Close class - Limits and tolerances
- Table 3 Coarse thread series (B.S.W.) - Internal threads - Medium class - Limits and tolerances
- Table 4 Coarse thread series (B.S.W.) - External threads - Medium class - Limits and tolerances
- Table 5 Coarse thread series (B.S.W.) - Internal threads - Normal class - Limits and tolerances
- Table 6 Coarse thread series (B.S.W.) - External threads - Free class - Limits and tolerances
- Table 7 Fine thread series (B.S.F.) - Basic sizes
- Table 8 Fine thread series (B.S.F.) - External threads - Close class - Limits and tolerances
- Table 9 Fine thread series (B.S.F.) - Internal threads - Medium class - Limits and tolerances
- Table 10 Fine thread series (B.S.F.) - External threads - Medium class - Limits and tolerances
- Table 11 Fine thread series (B.S.F.) - Internal threads - Normal class - Limits and tolerances
- Table 12 Fine thread series (B.S.F.) - External threads - Free class - Limits and tolerances
- Table 13A Selected thread series (Whit. S.) - Preferred diameters and pitches - Fractional sizes
- Table 13A Selected thread series (Whit. S.) - Preferred diameters and pitches - Fractional sizes (continued)
- Table 13A Selected thread series (Whit. S.) - Preferred diameters and pitches - Fractional sizes (continued)
- a) up to and including 1 in: the nearest in size;
- b) above 1 in up to and including 6 in: the nearest in size;
- c) above 6 in: the nearest in size. [Go to Page]
- Table 13B Selected thread series (Whit. S.) - Preferred diameters and pitches - Decimal sizes
- Table 13B Selected thread series (Whit. S.) - Preferred diameters and pitches - Decimal sizes (continued)
- a) up to and including 1.5 in: the nearest 0.030 in size;
- b) above 1.5 in up to and including 6 in: the nearest 0.060 in size;
- c) above 6 in: the nearest 0.125 in size. [Go to Page]
- Table 14 Selected thread series (Whit. S.) and non-standard threads - Depths of thread for various pitches
- Table 15 Selected thread series (Whit. S.) and non-standard threads - External threads - Medium and free class - Allowances
- Table 16 Selected thread series (Whit. S.) and non-standard threads - External threads - Close class - Tolerances
- Table 17 Selected thread series (Whit. S.) and non-standard threads - Internal threads - Medium class - Tolerances
- Table 18 Selected thread series (Whit. S.) and non-standard threads - External threads - Medium class - Tolerances
- Table 19 Selected thread series (Whit. S.) and non-standard threads - Internal threads - Normal class - Tolerances
- Table 20 Selected thread series (Whit. S.) and non-standard threads - External threads - Free class - Tolerances
- Annex A (normative) Truncated Whitworth form threads with flat crests [Go to Page]
- A.1 Profile of truncated Whitworth threads
- A.2 Limits and tolerances [Go to Page]
- A.2.1 General
- A.2.2 Limits and tolerances on the major diameter of external threads and the minor diameter of internal threads
- A.3 Designation
- A.4 Gauging system [Go to Page]
- a) for external threads: [Go to Page]
- 1) GO screw ring or calliper gauge;
- 2) NOT GO effective diameter calliper gauge;
- 3) GO plain calliper gauge for flat crests;
- 4) NOT GO plain calliper gauge for flat crests;
- b) for internal threads: [Go to Page]
- 1) GO screw plug gauge;
- 2) NOT GO effective diameter plug gauge;
- 3) GO plain plug gauge for flat crests;
- 4) NOT GO plain plug gauge for flat crests.
- Figure A.1 Tolerance zones for truncated Whitworth threads (close class external thread and medium class internal thread) [ in B.S.W. (20 t.p.i.) illustrated] [Go to Page]
- Table A.1 Truncated threads - Whitworth form - Basic data
- Table A.2 Truncated threads - British Standard Whitworth (B.S.W.) series - External and internal threads - All classes - Limits and tolerances
- Table A.3 Truncated threads - British Standard Fine (B.S.F.) series - External and internal threads - All classes - Limits and tolerances
- Annex B (informative) Bases of tolerances and allowances for Whitworth form screw threads [Go to Page]
- B.1 General
- B.2 Tolerance classes
- B.3 Allowances
- B.4 Tolerances on effective diameter
- B.5 Tolerances on major diameter [Go to Page]
- B.5.1 External threads
- B.5.2 Internal threads
- B.6 Tolerances on minor diameter [Go to Page]
- B.6.1 External threads
- B.6.2 Internal threads
- B.7 Minimum depths of engagement
- Annex C (informative) Tolerances on pitch and flank angle in relation to tolerance on effective diameter [Go to Page]
- C.1 Effect of pitch errors
- C.2 Effects 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. The simple effective diameter of an external thread (as measured along the pitch line of the thread) should...
- b) Internal threads. The simple effective diameter of an internal thread (as measured along the pitch line) should lie between t...
- Annex D (informative) Form of the crests of Whitworth threads [Go to Page]
- D.1 General
- D.2 Internal threads
- D.3 External threads [Go to Page]
- Figure D.1 Crest forms resulting from different production methods
- Annex E (normative) Limits and tolerances for close class internal threads for special uses [Go to Page]
- Table E.1 Coarse thread series (B.S.W.) - Internal threads - Close class - Limits and tolerances
- Table E.2 Fine thread series (B.S.F.) - Internal threads - Close class - Limits and tolerances
- Table E.3 Selected and non-standard threads - Internal threads - Close class - Tolerances
- Bibliography [Go to Page]