Joe LaTassa wrote:
-----Calling all crank cognoscenti!
About my 30s vintage Hamel with a threaded sleeve BB arrangement: Can anyone tell me whether it is normal that a Bayliss-Wiley fixed cup should NOT be flush with the BB shell if it is fully screwed down (reverse thread, if that matters).? Looking at the cup, it seems to have a shoulder that might prevent it from fitting flush.? I also have other spare BW fixed cups that look the same...
The BW cups and spindle am using were original to this bike when I got it decades ago, but at the time I removed it and now cannot remember whether a small gap existed there or not.
Thank you very much!!!! +++++++++++++++++++++++++++++++++++++++++++++++++
My Hamel has a Bayliss-Wiley "Unit Bottom Bracket," which was discussed some months ago on the list. I think that's the official name for the "threaded sleeve BB arrangement" Joe describes. Basically, the Hamels were lugless. they used a slightly oversized bb shell, into which the B-W unit was mounted. It was held in place by the bb cups, which grabbed the edges of the outer shell. I've thought about why these units were developed and sold, but no firm conclusions. It did make life a bit easier for the lugless builders, who could buy a pre-manufactured unit and just use tubing for the outer shell. Only had to worry about alignment and length, and not about threading (I suspect that most lugged bbs came pre-threaded at the time???). Or, I dunno.
The B-W fixed cup and lockring have a slightly different shape from conventional cups, to accomodate this, with a slight lip cut into the inner face of the retaining surface. I have a picture of the assembly from an eBay auction some kind lister flagged. My Hamel shows no gap between the frame's bb shell and the cup or lockring of the unit BB.
harvey sachs
mcLean va.