Updated in second post, below.
I've tried the search function, without joy - I know this must be a common issue.
I'm building up a NOS, 1979 Raleigh Record (531 throughout). I presume it needs an english threaded bottom bracket, which I have. How do I tell if it is 24 tpi or Raleigh's own 26 tpi? Do I need to rely on my eye sight to try to count threads inside the bb shell?!
Assuming it is a proprietal Raleigh bb threading , what are the options? V I see Velo Orange do a threadless (internally expanding) bb, which is mentioned on Sheldon B's site. Are there many (!) Raleigh bb's around - if so, where do I look - E-bay doesn't look overly promising from my initial look.
Any help gratefully received,
NB - A proper write up and pics will follow in due course.