Threads on A65

[chrisx1]

Can someone please remind me what the threads are on 1968 A65 engine cases. And what was used on 1963 frames, forks etc. I seem to remember that they are different.

[chrisx1]

Non of the books tell me if a bolt is Whitworth or bsf etc. I know thread counts and sizes but I want to know if it's British cycle thread etc..

[chaz]

depends which bolts you need to know?
thin sections or areas needing a fine thread, would be BSF, BSC or UNF for the later , mainly USA market.
material like cast aluminium where a thin thread could strip or pull out would use BSW or UNC.
the coarser thread gives more material between the pitches to prevent stripping.

smaller threads would normally be B.A. but rarely Americans would use no (number) threads eg 6x32 unc.

best thing I would suggest , find out which bolt or thread you need to know and consult the relavent parts book. Then do a google search and places will possibly give the thread. Baxter in America list most sizes . eg
1/.
https://draganfly.co.uk/product-category/bsa/sparesparts-for-bsa-a50-a65/1968/crankcase-alternator-68/
2/.
#25   68-0031  crankcase bolt 
3/.
https://www.baxtercycle.com/product/68-0031/

this search gives 5/16" x 3-1/8" x 26tpi     5/16" x 26tpi would be the norm BSC tpi


if you cant get hold of a Zeus book or thread charts use https://www.wdscomponents.com/en-gb/thread-dimensions   this is useful for the tpi of threads

[Stubaker58]

Look online for the BSA fasteners list, it references the part number against the thread type.

[chrisx1]

I've downloaded the list now. Thanks guys for the help.