It looks like that has to do with surface texture. I can reliably feel a step of 0.005" (0.13mm). I doubt if steps under 0.001" (0.03mm) can be felt. Nowhere ne

It looks like that has to do with surface texture. I can reliably feel a step of 0.005" (0.13mm). I doubt if steps under 0.001" (0.03mm) can be felt. Nowhere near atomic scale.