I had a little dilemma buying a wrong headset. Being the newb I am, I didn't realize there were ISO and JIS versions of the Tange-Seiki headsets. Anyway, I grinded the head tube CAREFULLY counting the circles and finally finished it off with the sanding bit. I do know they make reamers, but I could of just bought a different headset. It's a cheap track frame (SE Premium Brew) so I'm not worried too much, however, I am worried if ~0.2mm off or so will cause premature wear. Also, for the fork, it was weird because the crown race was uber small - I ended up grinding the crown race since it was easier. Has anyone done this before, or is this highly not recommended?