The width of the cuts on my bushing puller are just a hair wider than 1/32 of a inch.
Do they sell grinding wheels in different widths?
Cutoff wheels are generally 1/16" thick. That would probably do the job for you. Clamp the tool snugly in a vice and very carefully run the cutoff gently into the slot, bracing your hands and being careful not to put the wheel in a bind or it will catch and possibly blow up on you.
Make sure the guard is on the grinder, and wear a full face shield and welding gloves.
