Re: [CR] Italian thread fixed cup

Not only the Italian, but also the French screw the same BB thread direction. This has been a small problem thru the years, usually as mentioned by not sufficent tightening. For years as long as I can remember into the '40s we saw how to fix the problem. First proper tightening, never had one come loose when good and tight. Many times we saw that someone took a nice sharp point punch and hit the BB shell right next to the flat and thus made a small bulge that overlapped the flat to prevent "backing off". One could file this small bulge down when removing, but the BB cup would always unbulge when properly held tight and turned out. Chrome plated BB's and fancy restos were not an issue, riding was. This is very similar to the block chain bolt and nut fastening screw and nut. Smart mechanics would tighten the bolt for the proper play and flex looseness then tighten up the small nut, and with a backplate stop tap the screw thread just a little to flatten a thread just a litttle to keep the nut from backing off. When taking the chain apart holding a scewdriver in the slotted head and then unscrewing the nut with a plier, the nut would always reform the thread and it would come apart very easily. On another note, the ball bearings in the cups are rotating in the direction of crank motion. The individual balls are rotating in the opposite direction, however. Which leads to the question: Which of these rotating forces are greater? Or is it more a matter of power and stress on the BB housing and cups when the cranks are being brutalized by thundering thighs? Curious minds want to know.
Ted Ernst
Palos Verdes Estates
CA USA