Most people who work in bolt shops were not born when BSF & BSC (cycle thread) were last in common use. Often they will look at you blankly when asked. Bruce Gardner, B.S.F. Bolts, 0408 056 255, is the best source in Australia for BSW, BSF, BSC, BA nuts and bolts as well as currently used systems. He is also the best for BA taps and dies including the very rare left hand ones. (Better and cheaper than that un-named South Australian lot).
It has become very difficult, if not near impossible to source high grade hardware ( equivalent SAE grades 5 & 8) in British threads in recent years. You can nearly guarantee that anyone with stocks of these has very old stock. BSW socket head cap screws disappeared from the Unbrako catalogue at least 10 years ago.
My business, Brian's Retirement Sale, does not handle nuts and bolts, but my speciality is rare, obsolete, hard to find, and "no longer available" taps and dies. I have BSW, BSF, BSC, CEI Coarse, BSP, NP, UNC, UNF, UNEF, UNS, UN 24 pitch, Metric. My stock is intended for machine shop use so all taps and dies are in high speed steel, not cheap tools in carbon or chrome tungsten steels. I stock screw pitch gauges in BS, UN, Metric. If you wish, send me your e-mail address and I will send you thread charts.

