Bloody he%#, after Mick's earlier post I'm going to go put Marmite on my tofu.
Today I received a couple of 50's-early 60's Japanese track frames. There is a peculiar bb shell arrangement on both bikes, at least it is something new to me. The drive side shell lip has two square nubs sticking out from the edge, 180 degrees from each other. The other side of the shell has the inside 4-5mm chamfered, so the actual outer edge is quite thin and sharp. It would seem that the drive side bb face would be penetrated by the nubs so as not to turn, while the other side face would pull into the taper while being tightened. How that tightening might be accomplished I don't have a clue. Was such a bottom bracket shell ever utilized outside of Japan? Has anyone else encountered such?
Thanks in advance.
Dennis Young
Hotaka, Japan