Last night at Nova Labs, one of the woodshop folks asked if I could help free a stuck router collet nut. We put a breaker bar on a pair of wrenches and managed to break both wrenches without moving the nut at all. I decided to take it home and work on it there.
What had happened, as best I can reconstruct it: someone put a regular end mill (not a router bit) into the collet and pushed it in so far that the flutes bit into the side of the collet. The end mill was too big to be the right tool even if it had been the right kind of tool. When the nut got cranked down, I think the flutes dug into the nut as well, and between that and the mangled threads on the collet holder, the nut, end mill, collet, and holder had become one solid lump.
That's all just a guess on my part, though.
At home I tried everything I could think of. I tried boring out the end of the nut on the lathe, but the nut is hardened and even my carbide tooling wasn't really up to it. I tried heat. I tried WD-40. I tried an impact driver, which didn't budge it either.
I even put it on the surface grinder to see if I could grind the end off, but that was slow enough that I wasn't happy with the result.
In the end I grabbed the angle grinder and cut the nut off, carefully.
That obviously destroyed the nut, but the collet came through all right.
The collet holder is another story: it's so messed up that I think we'll just buy a new one. We looked over the damage together and it's probably too severe to reuse safely.
