Unless you have a brake drum lathe that cuts both sides of a rotor at the same time, it's very unlikely you'd be able to hold the .0005" parallelism from side to side that rotors need. Maybe with a very accurate lathe, a faceplate, and a tool post grinder? They're probably not warped- - - -the sides aren't true to each other. Half a thousandth is a strand of red hair- - - -split into three equal slices.
Jerry
