There is a lot of helpful background info at the Centric site. It's heat-treating that is often inadequate in China, not just machining. I probably didn't go into enough detail. It's not specifically 'poor-quality metal' to start. I've looked into this in the past.B10alia said:I don't think that machining in the US is going to help anything in terms of wear. Poor-quality metal is poor-quality metal. Not to say that the Chinese aren't capable of making good steel or cast iron, they certainly are, but good metal is more expensive to make. The assumption nowadays is pretty much that rotors get junked with pads, because they're so cheap.
I just measured my credit cards with a vernier caliper. I got 0.031 inches each. So if you were worn down 0.062 inches, those rotors were shot, the way they make them today. You were past the hardened surface and cutting into the softer iron.neon98rt said:2 credit card per side
Yes. The official wearout is determined by measuring the thickness of the rotor vs what is stamped into it as a minimum. However, in the old days, there was .050" or more of hardened surface on each side. So even old, quality rotors would be worn at this stage. Typically back then, you could turn a rotor twice, removing .030 inches each time. Do that once today, and you have already removed the softer metal.B10alia said:.062 per SIDE, Bob. Almost an eighth of an inch overall. I wouldn't buy that brand again.