Two options come to mind...
TIG weld a couple of steel rods onto the remainder of the cup. MIG would also work, but the tip is larger and you have the splatter to get rid of. You can wrap the BB in damp rags to prevent paint damage. After that, clamp the protruding rods in a vise and twist the cup out. I have TIG welded extensions onto broken-off studs where only the sheared end is visible...it's a very precise process, and works wonders.
You can get in there with a Dremel cut-off wheel, if you must. The cuts would be spiral, but it would work. The Kevlar cut-off wheels probably start out a tad large to easily fit, but they wear down to much smaller diameters. I just took one off my mandrel yesterday that was down to about 1/2" diameter.
Scott Minneman San Francisco, CA USA
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of Carb7008@cs.com Sent: Tuesday, October 27, 2009 10:47 PM To: classicrendezvous@bikelist.org Subject: [CR] Broken Fixed-Cup Removal at SBK
Here in Sacramento we have a volunteer bike-biz catering to folks. A gentleman came-in tonight with a loose crank,which upon removal of BB, the fixed cup had circumferentially broken in-two such that about 3/4" of the inner portion of cup remained threaded in the shell about 1/4" deep. Every effort to remove, including un-screwing, cutting with hacksaw, notching with file, prying with screwdriver, failed to remove hardened (why do you think they call them "fixed"?) race.
I doubt a cold chisel, which we didn't have, would have cut-through. A Dremel tool may have worked if we could have gotten the cutting-wheel inside
the BB shell. Needless to say, the gentleman walked his OT bike home. Any ideas short of torch or liquid nitrogen embrittlement?
Jack Romans
Sacramento, CAlifornia