Jim
Just been browsing your info on threading and you mention 'BSA' threading. That information is incorrect. BSA (Birmingham Small Arms) Cycles Ltd, a bicycle manufacturer did use a cycle thread 31/31" x 30TPI C.E.I. (Cycle Engineers Institute thread) which is no longer listed under the British Standard/ISO British Standard Cycle threads. The thread size disappeared in the rationalisation of British cycle threads. The standard BSC bottom bracket thread is 1.375" x 24 TPI B.S.C. x 68mm (1 3/8" x 24 TPI in old money. Don't know why they decimalized an imperial fraction) The BSC stands for British Standard Cycle which relates to the type and shape of the threads (adopted from the C.E.I.). The BSC threads are left and right threaded unlike French and Italian which are 35mm x 24TPI and 36mm 24TPI respectively and both cups are right threaded. BSC threads of various sizes were also used for hub axles, pedal axles, headset/fork steerer tube, freewheels seat post pinch bolts. Campagnolo used a unique system of 9mm x 24 TPI axle thread for front hubs and 10mm x 24 TPI for their rear hubs. Most of the modern manufacturers seem to be following Shimano with a metric thread of 9mm x 1mm and 10mm x 1mm for hub axles. Sachs-Maillard tended to use BSC thread on their solid axles and metric on their quick release axles just to confuse the issue! By the by I have found that the allen key expander bolt on the 1980 Peugeot's French handbar stem was 7mm not the standard 6mm. The oft quoted 'BSA' is meaningless as it is a bastardisation which means nothing in engineering terms. It is a oft repeated by journalists in the popular cycling press but just goes to show the extent of how little they actually know and how poor they are at research and checking facts.

Chris