[JimmieS]

Many thanks for the quick replies.Much appreciated. I have a thread gauge plus set of tables but, like most things in life, I can;t find them when  needed. As none matched my BSF taps I assumed what I now know as fact.
Thanks again.
Jim

[shorrog]

Not sure if you have seen the tables of thread sizes on the website, but they can help when identifying a thread if you can measure dia and pitch.
https://www.marston-sunbeam.org/threads/thread_british_std_cycle.php


Graham

[singleminded]

Most frame thread up to 1932 seem to be 26tpi cycle..My '32 9A is mostly BSF on the frame, but you will find 20tpi and 26tpi cycle on some parts..The clutch nut for example was 26tpi up to 31ish and 24tpi from 31ish onwards..You need to have a thread gauge handy.

[JimmieS]

Dry building my long dismantled Model 2. Many bolts which seem original appear to have cycle threads. Is this so?
Jim