Uh, if your SW is worn so badly that it isn't flat, simply cutting new grooves isn't going to help much, I think. You'll need to mill the face flat, then regroove.
Sounds like this is probably correct.
As for which dremel disc to use, well, all of them are about the same thickness, which is thicker than the USGA rules allow.
I disagree with this. All the cutting disks I have are in the .025"-.030" range, which is under the USGA maximum.
However, if you insist on doing it, I'd suggest strongly that you practice on a club you don't care about. Or better still, draw an ink line on a piece of scrap metal and practice on that.
A club you don't care about might be a good idea. Trying to follow an ink line is so much harder than following a pre-existing groove (even a worn and shallow one) that it's not good practice for the real thing. OTOH, if you really did follow the first advice and mill it flat....
Good luck! DaveT
