I turned and drilled my stock rotors for my 97 chevy 1500 and 96 grand am. The reason was to reduce warping from heat build up. The grand am rotors lasted quite a while before warping. The ones on my truck are still not warped, even after several years and est 50k miles

I used a Bridgeport machine with adapter plate with degrees on it
I have not had cracking issues even after this long. Both cars are daily drivers