Am currently build up a 1974 Mercian as a Single Speed "about town" bike, new BB has landed but is really, really tight should my LBS have a tool to "ream"?
(Have tried Muckoff + Toothbrush + grease)
I'd find a local frame builder if i were you, they will have the know-how as well as the tools..
post a pic. when yer done sounds like a nice retro town bike. ta.
Are you sure your new BB has the correct sized threads?
Actually, you would only get this behaviour if the frame has a Raleigh bottom bracket shell and you're trying to fit a British/ISO BB. So it is unlikely that you have the wrong BB.
shouldn't cost you much to get your LBS to chase the threads and ream the ends. if the threads have rusted at all – not uncommon if the frame hasn't had a BB in for a while – then it'll need doing. don't force it!
The thread on your Mercian will be a 1.37x24tpi.
Which is the standard british frame thread.
Raleigh used to use a totally different thread.
Your Mercian will not use that thread.
We would charge about £15 to Tap & Face a frame.
So unless you are in the centre of London.
You may find a comparable price at your LBS.
They will definately have the tools & knowledge.
I guess it could be a good excuse to visit Grant at Mercian, although we have a newish LBS new me so might try him first.
Oh, Fringe, will post pic when complete.