Originally Posted by
Euclid440
So and metal, steel that is impact damaged, is never the same. As an example a body worked fender can be made smooth, on the finish side but looking at the other side the damage is clearly visible.
With a razor edge it is the thinness of the edge where it fails. It probably is a form of work hardening that makes it brittle and weak.
I use to raise serial numbers from firearms where numbers were ground off.
A stamped serial number is pretty deep, say 1/16 in, then the alter ground it a 32nd to a 16th beneath the bottom of the stamp. We would file the area smooth removing another 32nd to 16th and hit it with acid. The number would flash and remain clearly visible until the acid began to evaporate. Generally it could be repeated a couple more times.
So the damage goes pretty deep, possibly an 1/8 to a 1/4 of an inch or more.
Try bevel setting a razor on a 300 grit Diamond plate and then try to put an edge on it. For most, you will have to remove a bit of the edge, to get it to hold, often the edge will look ok at the low grits, but fall apart at the higher finish grits, micro chipping, when the edge is at its thinnest.