BS 949-3:1993

Committees responsible
Foreword
Specification
1. Scope
2. References
3. Right-hand and left-hand threads
4. Terminology of thread profiles
5. Types and sizes of taps
6. General dimensions
7. Dimensions and manufacturing tolerances for the
     threaded portion of taps for G series and Rp
     series threads
8. Dimensions of the threaded portion of taps for Rc
     series threads
9. Marking
Annex
A. (informative) Examples of the calculation of
     thread dimensions
Tables
1. Summary of the size designations of taps for pipe
     threads
2. General dimensions of taps for parallel pipe
     threads (G series and Rp series)
3. Dimensional tolerances on shanks and squares
4. Dimensional tolerances on length of thread and on
     overall lengths
5. General dimensions of taps for taper threads (Rc
     series)
6. Limits of tolerances
7. Dimensions and manufacturing tolerances for the
     threaded portion of taps for G series pipe threads
8. Dimensions and manufacturing tolerances for the
     threaded portion of taps for Rp series pipe threads
9. Dimensions of the threaded portion of taps for Rc
     series pipe threads
A.1 Calculation of the dimensions of the threaded
     portion of a G half ground-thread tap
A.2 Calculation of the dimensions of the threaded
     portion of an Rp half ground-thread tap
Figures
1. Thread profile of a nut with a G series thread
2. Thread profile of a tap for a G series thread
3. Thread profile of a nut with an Rp series thread
4. Thread profile of a tap for an Rp series thread
5. Thread profile of a nut with an Rc series thread
6. Thread profile of a tap for an Rc series thread
7. Tap for parallel pipe threads (G series and Rp
     series)
8. Tap for taper pipe threads (Rc series)
9. Nut and tap ptich diameter tolerances, G series
     threads
10. Nut and tap pitch diameter tolerances, Rp series
     threads
11. Threaded portion of tap for taper pipe threads
     (Rc series)
List of references

Specifies tolerances and dimensions for screwing taps for the following thread series: parallel internal pipe threads for use with taper external pipe threads in making pressure-tight joints on the threads; parallel internal pipe threads for use where pressure tight joints are not required to be made on the threads; taper internal pipe threads for use with taper external pipe threads in making pressure-tight joints on the threads. Also includes tables and diagrams.