Originally Posted by
3alarmer
...if the threads are already "all the way out of the hole", a full cut is going in the wrong direction. I know you are certain that (mm is the correct cotter for this application, but are you certain that 9mm is the correct cotter for your application ? If you don't have one of those Park spoke ruler gauges with the go/no go holes for cotters, you can use your crank arm as a gauge. With it off the bike, the uncut top portion of the cotter should just snugly fill the hole. If it shakes around in there, your cotter is too small. Or you can measure the one installed in the working arm at the top, with a vernier caliper.
Yes, it is 9.0. The crank is early 60s Simplex French. The cotter fits smoothly through the hole. An English 9.5 does not go in the hole at all. The batch of cotters I have are 8.8 to 8.9. Diameter varies pin to pin but each pin is straight enough.
My manual skills are pathetic. No pretending otherwise. I can measure and do it a lot. Only rarely make a measurement error and still measure everything at least 3 times.
My luthier friend measured the hole with a gauge from my dreams and says it is still round, not oval. Same for the bore hole where the spindle goes.