- BSPP – BRITISH STANDARD PIPE PARALLEL (G SERIES)
- BSF – BRITISH STANDARD FINE THREAD
- BSW – BRITISH STANDARD WHITWORTH COARSE
APPLICABLE STANDARDS; BS-21, BS 919, ISO 228, ISO 7-2, EN10226
BSPP, BSF & BSW are Whitworth parallel screw thread with a full angle of 55 degrees and one-sixth of this sharp V is truncated and rounded at the top and bottom (crest and root).