You are probably familiar with Acme Co.. It's where Wile E Coyote gets his anvil etc. I needed a fixed cup wrench to work on my Motobecane Le Champion and the one sold by the blue stuff company didn't impress so made the one shown below. The long bolt /washer holds it to the shell&cup and you put a breaker bar or

torque wrench or whatever on the captive hex head. You could probably twist the shell out of the frame if you wanted

Very impressive, have you made any other sort of tooling?

I brought an old Peugeot to a local that had the Var products to remove the 8 point cup.

I've made some other stuff as needed-chain whip, headset wrenches, a mandrel sorta thing to remove dent in seat tube from inside and drillium(ed) some chainwheels. Helps to have a milling machine and lathe.