Originally Posted by
alexnagui
However, I managed to take it off several hours ago. I went to my LBS where they have a proper vise which I could use. Once the fork was clamped into the vise, it was a matter of applying quite some force to remove it. But it got loose in the end! My theory got actually approved. The steerer tube got kinda expanded that's why the race wouldn't move. The guy at the shop chased the threads with a tap so the fork should be fine to use. However, when I got home I got to think whether he used the right tap for French threading
Terminology: If he chased the internal threads on the bearing race, he would use a tap. If he chased the external threads on the fork, then he used a die. Because bearing races are generally hardened, it would be more likely that he ran a die over the fork.
The obsolete French size is 25mm x 1mm. The more recent ISO size is 1" x 24TPI. If you think about this, if you used an ISO die on a French-threaded fork, you'd be taking 0.4mm off the diameter or 0.2mm off the radius. Both threads use a 60° thread profile, so the original thread depth of about square root of 3 over 2 times 1mm would be 0.866 mm. You'd be taking 25% of the metal off the threads, you'd be generating a hell of a lot of metal filings ("swarf") and (IMHO) you'd have as hard a time getting the die started and turning it as you had removing the race.
Because this difference is pretty obvious, I suspect that your bike shop guy did not use the wrong die and you should be ok. Does the race screw onto the fork easily? If so, your fine. When you re-install, remember that you don't have to apply a lot of torque to the race. Enough to get the pin under one of the holes in the washer conveniently. And use grease on the threads to prevent corrosion, rust, and the threads locking up over another 45 year period. The bike should be good to ride in 2073!
Taps (long skinny things) and dies (discs with holes):
