gabriel l romeu wrote:
> I have no framebuilding expereince, nor whether bottom brackets are ever
> threaded before the tubes are brazed on, but it would be a relatively
> simple operation to do a through thread in perfect aligment on a lathe.
Italian and French threading are particularly amenable to threading on a lathe as they are RH thread on both sides. Many builders use lathes to cut these threads. English and Swiss threading uses LH threads on the fixed cup side, so piloted taps are used in this case.
And yes, most BB shells are threaded before assembled into frames; after brazing you need only chase the threads with a tap or lathe.
--
John (john@os2.dhs.org)
Appleton WI USA