[varjag]

A typical metric micrometer is accurate to 0.01mm (tho you can find more precise ones at premium). It's really unlikely you'll get a micron precision from any calipers. Even an angry glance warms up the instrument enough to make this meaningless.

Microns are the domain of grinding and lapping, you rarely ever need to go there with cutting.

[genewitch]

you're right, the 3d printer i had was accurate to "within 20 microns" which is what my decent metal calipers can measure. 20mm = 20mm within 0.02mm.

I've already started calling the fab size of my processor as 80 angstroms (or whatever), so i probably back-propagated that.