Hi, I just bought a second hand hudy tech lathe and I've set it up with the tip just above the center of the comm and have it spinning the correct direction but it is leaving serrations in the comm. I'm using v guides and shimming the armature a little bit to eliminate the play.

Any help greatly appreciated.

What kind of cutting tool are you using? If it's Carbide, throw it away and get a Diamond Bit. It will last longer and cut better. Those carbides bits work good, but the dull quickly.

Its a diamond tip.

Is it damaged??

Tried varying motor speed or how fast you turn the wheel for bit travel??