Originally Posted by
nitropowered
Couldn't the bottom bracket cup chip the paint and expose the bare steel?
Good point. If your tools are sharp, you should get a nice edge to the paint. I then put a liberal amount of grease on the freshly faced shell for just this reason.
Originally Posted by
nitropowered
Anyway, I normally face and chase shells if a customer brings in a frame and wants an external BB crank installed. I hardly ever take apart an OE build to face/chase unless its being build for a special customer or has specifically requested it.
+1
Originally Posted by
nitropowered
One question for all you wrenches, what do you do with carbon bikes with aluminum or ti bottom bracket shell inserts? It seems risky to try to face those shells. I built up a carbon bike recently (I think it was an ADK frame) with a Al BB shell insert. The faces didn't look to be perfect but I played it safe and didn't face it. A ruined BB < ruined frame
For Aluminium: Since the inserts are often 2 pieces that are bonded into the carbon frame, you are at the mercy of the frame maker a bit more if there is damage (although maybe a damaged cup could be replaced by someone like Calfre? Not sure here). I'd still face and chase.
For Ti: If it's a Ti frame and isn't painted I'd leave it. Most shops don't have the proper cutting tools for Ti anyway. I'd be interested in hearing what others do here, as well.