I am a real fan of the cheap HF lathe bits. (key word here is cheap) Many times I touch mine up on my normal bench grinder, with about a 100 grit silicon oxide wheel on it. If I need to, I will finish it on the carbide grinder that has 100 grit green wheels on it. For major reshaping, I use the standard bench grinder, because in addition to just grinding the carbide, I am grinding a lot of the underlying steel also and I don't like to tear up my green wheels.