Originally Posted by niknak

If you are going to use calipers to measure the rotor thickness, make sure you're not measuring the thickness of the rotor edges, which typically don't get touched by the pads. You'll get a false reading that your rotor still has life left.

I put a pair of short pieces of welding wire, one on each side of the rotor's middle section, and measure the total thickness. Then measure the thickness of each bit of welding wire and subtract it from the total thickness you measured first. That'll get you an accurate thickness.

A micrometer is a better tool for the job though.