BB86 reamer/facer?

So against my better judgement, I was convinced by a buddy to build him a new road bike with a bb86 shell. Main reason being he wanted uber oversize tubing (38mm dt/31.8 st/tt, 44mm ht) and wanted the bb to be in proportion. I did my best to keep the heat down while welding the bb, but alas either warping or just the undersized nature of the shell has left me with a bike I can't get a bb into. I've searched the internet and haven't had much luck finding an off the shelf reamer/facer. Anyone have any insight as to an alternate method of reaming the bb shell or where I could find a tool?

milling machine, boring head and boring bar is not really that hard to use. Never done it with a bike, but I did a repair to my lathe cross slide this way.

Expanding reamer? Then facing tool with custom (bodged) pilots?

park tool #752 BB30 reamer and have it reduced / reground by a reputable tool grinding shop ? (needs to be 41.0 +0 -0.05mm)

that way you can use #690 or #690XL depending on the OD of the shell to face in a single pass (may need a spacer for extra cutting depth)

don't forget the bevel on the inside of the shell, 1mm +-0.5mm at 45 degrees is usual, but necessary for the bb to sit against the faces of the shell because of the small radius on the internal corner of the BB itself

just a thought

best of luck

NBC

Thanks for all the ideas. I'm gonna talk to a buddy at a machine shop and see if there's a way we can fixture the frame and bore it out with a boring head. I don't trust my skills enough to attempt that at home. If (and that's a big if) I ever decide to build another frame with the bb86/92 standard, maybe then I'll look into having a bb30 reamer modified. As of this moment, this frame has been kind of a PITA so I doubt I'll build another in the near future. Although I will say I think it turned out pretty nice.

Thanks again to all.

Quote:

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Originally Posted by Erasmus

Thanks for all the ideas. I'm gonna talk to a buddy at a machine shop and see if there's a way we can fixture the frame and bore it out with a boring head. I don't trust my skills enough to attempt that at home. If (and that's a big if) I ever decide to build another frame with the bb86/92 standard, maybe then I'll look into having a bb30 reamer modified. As of this moment, this frame has been kind of a PITA so I doubt I'll build another in the near future. Although I will say I think it turned out pretty nice.

Thanks again to all.

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you mean something like this

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