I turned my solid Will Woods 20 years ago when the pad went metal on metal. Still have those brakes from the old car on the new car. The shavings came off in curls. Totally unlike machining a normal rotor. They have some grooves now. I just swap in new pads. They seat on the first pass. Stop fine from [email protected] I also foot brake up to 3300. I'll bet there are 2000+ passes on them. No issues. The vented front rotors have been replaced a few times due to heat cracks. Changed pads on them multiple times as well. Never touch the rotors. Just clean everything up on the caliper and slide them in.