BS 949-2:1992
Current
The latest, up-to-date edition.
Screwing taps Specification for unified ground thread taps. Manufacturing tolerances
Hardcopy , PDF
English
15-12-1992
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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
|
| BS 93:1951 | Specification for British Association (B.A.) screw threads with tolerances for sizes 0 B.A. to 16 B.A. |
| BS 1580-3:1965 | Specification for Unified screw threads Diameters below ¼ in |
| BS 949-3:1982 | Screwing taps Specification for taps for pipe threads (G series, R<sub>p</sub> series and R<sub>c</sub> series) |
| 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 |
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