Classic car enthusiasts are familiar with the world’s first national screw thread standard, BSW (Whitworth), devised and specified by Joseph Whitworth in 1841. By mid-century the Whitworth standards of measurement were thoroughly recognised and established throughout the UK, the standard being used by the military, the railways and into the twentieth century with motor car and motor cycle manufacturers. There are two standards of Whitworth fasteners, as during WW2 the sizes of nut and bolt heads were reduced to save metal, but reduced by one full size, so that the same spanners and sockets could be used. The fasteners were most phased out by the 1960s but are still found on older classic cars and motorbikes and of course are still specified when carrying out a fastidious and correct restoration.

This new Tap & Die set from Gunson (part no: 77123) displays the company’s commitment to continuing the supply of Whitworth tools and is suitable for cleaning and repairing these threads.

A comprehensive set, it includes one tap wrench and one die wrench plus 7 dies: 1/8-40BSW, 3/16-24BSW, 1/4-20BSW, 5/16-18BSW, 3/8-16BSW, 7/16-14BSW and 1/2- 12BSW.

Fourteen taps are included (taper and plug): 1/8-40BSW, 3/16-24BSW, 1/4-20BSW, 5/16-18BSW, 3/8-16BSW, 7/16-13BSW and 1/2-12BSW.