Screwing taps Specification for unified ground thread taps. Manufacturing tolerances

Available format(s)

Hardcopy , PDF

Language(s)

English

Published date

15-12-1992

Publisher

British Standards Institution

Committees responsible
Foreword
Specification
1. Scope
2. References
3. Right-hand and left-hand threads
4. Tolerance classes of taps
5. Dimensions and manufacturing tolerances of the
     threaded portion
6. Marking
Annexes
A. (informative) Bases of calculation of the
     tolerances on the threaded portion of taps for
     Unified threads
B. (informative) Example of calculation of the
     dimensions of the threaded portion of a tap
C. (normative) Taps for BSW, BSF and BA threads
     (obsolescent)
Tables
1. Formulae for limits of tolerance for ground thread
     taps for Unified threads
2. Dimensions and manufacturing tolerances for the
     threaded portion of UNC taps
3. Dimensions and manufacturing tolerances for the
     threaded portion of UNF taps
4. Tolerances on cumulative pitch for ground thread
     taps for Unified threads
A.1 Values of elements based on pitch in basic formulae
     for taps for Unified threads
A.2 Values of elements based on nominal diameter in
     basic formulae for taps for Unified threads
A.3 Values of elements used in calculating the minor
     diameter from a measured value of the pitch
     diameter of a tap for Unified threads
A.4 Tolerances on thread angle of taps for Unified
     threads
B.1 Calculation of the dimensions of a ground thread
     5/8 - 11 UNC tap, class 2
C.1 Dimensions and manufacturing tolerances for the
     threaded portion of BSW taps
C.2 Dimensions and manufacturing tolerances for the
     threaded portion of BSF taps
C.3 Dimensions and manufacturing tolerances for the
     threaded portion of BA taps, class 2
C.4 Formulae for limits of tolerance for taps for BSW,
     BSF and BA threads
C.5 Values of elements based on pitch in basic formulae
     for BSW and BSF threads
C.6 Values of elements based on nominal diameter in
     basic formulae for BSW and BSF threads
C.7 Values of elements used in calculating the minor
     diameter from a measured value of the pitch
     diameter of a tap for a BSW or BSF thread
C.8 Values of elements used in calculating the minor
     diameter from a measured value of the pitch
     diameter of a tap for a BA thread
Figures
1. Relationship of tap classes to nut tolerances
A.1 Minimum values of tap major diameter d
A.2 Tap minor diameter d1
List of references

Specifies tolerances and dimensions for screwing taps for various threads. Coverage includes: right-hand and left-hand threads; tolerance classes of taps; marking; dimensions and manufacturing tolerances of the threaded portion. Also includes annexes, tables and diagrams.

Committee	W/-
DevelopmentNote	Supersedes BS 949-2(1979) (12/2004) Supersedes 90/79112 DC (10/2005) Reviewed and confirmed by BSI, January 2011. (12/2010)
DocumentType	Standard
Pages	28
PublisherName	British Standards Institution
Status	Current

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BS 1580-3:1965	Specification for Unified screw threads Diameters below ¼ in
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BS 1580-1&2(1962) : 1962	SPECIFICATION FOR UNIFIED SCREW THREADS - DIAMETERS 1/4 INCH AND LARGER
BS 84:1956	Specification for parallel screw threads of Whitworth form
BS 949-5:1990	Screwing taps Nomenclature and terminology