AJS & Matchless Owners Club

Hi, I have come a bit late to this, but BSC threads are NOT a BSF/Whit thread form. They have a 60degree thread angle, whereas BSF/Whit threads are 55 degrees. They do, however, all use the same hexagon sizes, but are most definitely not interchangeable. AMC used BSC on nearly all steel/steel fastenings, BSF on steel into alloy or cast iron, BA for small stuff and a few special threads for things like big end nuts that wise men leave alone! Cheers, Andy

I will probably get my wrists slapped here but 1/4" BSF and 1/4" British Standard Cycle thread are close enough to interchange on non crical components, both being 26 TPI. The 5 degree difference in thread angle does not make a lot of difference.
The TPI is different in all other sizes.

Jim

I am with you Jim, (also expects a slap) a few degrees don't make much difference and the quality of threads these days you wouldn't notice. So lets not get into peak chamfers, root rads and effective dia.

Colin