British Standard Whitworth Screw Thread

British Standard Whitworth Screw Thread Form

Sir Joseph Whitworth developed this screw thread in 1841 in England. It is thought that this was the first standardized screw thread form. The principal features of the British Standard Whitworth screw thread form is the 55 degree included angle between the screw thread flanks and the radii at both the root and crest of the screw thread. The Whitworth screw thread form is not commonly used for nuts and bolts because it has mostly been replaced by the Unified-Series and Metric-Series screw threads. The Whitworth screw thread form is still the standard for pipe assemblies in the European Community.

The British Standard Whitworth screw thread form is found on several thread series:
British Standard Whitworth (BSW) is defined in BS 84.
British Standard Fine (BSF) which has a finer pitch than the BSW screw thread and is defined in BS 84.
British Standard Pipe Taper (BSPT) which is now referred to as the R-Series screw thread and is defined in ISO 7; EN 10226; BS 21 and formerly in DIN 2999.
British Standard Pipe Parallel (BSPP) which is now referred to as the G-Series screw thread and is defined in ISO 228 and formerly in BS 2779.

This data is accurate to the best of my knowledge as of 12/3/2008.
Send comments or corrections to Wayne at: office@gagecrib.com