Moving along wonderfully on my 1944 BSA M20 and decided to start bolting things together, went to the awesome manual that Henk sent me (thank you!!!!), and it only lists part numbers and not bolt sizes, thread count or lengths! Is there a reference chart that explains the sizes? For example "Tool Box Strap Bolt" Part Number 15-7161?!? I see the nut, EB113 is 1/4", but it doesn't even say if it is 20 or 28 TPI. Just when I thought I was making headway!
Please help!😂
Try these two pages from Draganfly. they may help to explain some of the threads used, however the part # list is not extensive as the bolt # you quoted is not listed:anguished:
To the most part, the fixing nuts and bolts and studs 1/4-5/16-3/8 are all BSCyc 26TPI the lengths can be determined by the neatness of only having a couple of threads protruding from a tightened nut. There are some exceptions such as larger size studs that have a 20tpi BSC thread.
There are also BSF and Whitworth threads on the engine etc, and more usefull info in the technical section. Ron
