Back when I worked at the NAPA (High School) we had a grinding attachment that would grind the inside of a drum as it turned on the lathe. If you got a drum with discolored hot spots on it the bit would "Jump" those spots & chatter like krazy if you tried to turn it conventionally.
Sometimes the drum was ground after turning to produce a superior finish than you could get using the tri cornered cutting bit.
Here's a link to a user manual PDF:
http://www.manualsdir.com/manuals/55...m-grinder.html
We also had a tool that ground on the shoes- was called "Arcing" the shoes. Brake shoe dust going everwhere, no dust mask or nuthin. Ah, the Good Ole Days!
