What thread was used on aircraft up to and during WW2 ?

Thanks for the info, more for my note book.
Phill

Bruce
Thanks for the information.will add this to my note book,

Thanks for the information on threads,I like the rhyme you were taught I will remember that and pass it on to fellow members.
Just trying to clean up some mushroom headed threads ,after someone in the past did’t use a soft drift to remove a pin.
Phill

I remember that; when I trained as an apprento in 1984, we used old Chipmunk and Provost manuals and the instructor had little rhymes or mnemonics to help us remember the threads; BA/BSF/BSW (British Aircraft, ie, BA) and AC or AF for American aircraft (Across Flats, for spanner jaw gaps)…..AN/MS/NAS for hardware. there was also UNF and UNC for American threads on pipes.

BSW in castings for studs.

Yes, mostly BA and BSF threads

British Standard Pipe threads… (Parallel or tapered…BSP-BSPT)… for Hydraulic, Pneumatic and Fuel pipe couplings.

British association for the smaller sizes, and British standard fine for the larger ones, with some exceptions depending on manufacturers whims. For example, de Havilland used metric threads on Gipsy engines.