Hi, I am new here driven primarily by my hobby of restoring older bicycles. I am not at present a machinist though I have an interest. I've dabbled in metal working in the past as well but time, and children, and money are all factors as well. Anyway, on to my specific question. I've come across a cup and cone bottom bracket for a 70mm shell. This is from the 1970's and not normally an issue as the Italian standard was 70mm shells. But the threading on these cups is English. English threaded cups use a 68mm shell so there's one mismatch. The other one is that the spindle is tapered 3 degrees instead of the standard 2 degrees. The best option is probably to find the pieces in better shape than mine, another option is to try and use a modern sealed cartridge which according to some should work but then I can't use the original crank. My question here is how hard is it to machine pieces like this, can they be repaired? The races for the bearings on the moving cup are a bit worn. I hope this question makes sense.