Com Lathe markings
Most Lathes are marked in either .000" or .00mm's. and depending on the lathe, turning the dial one mark will cut twice that amount. So one marking .001" actually cuts .002" from the
Com.
With an average cut being .002" that means about10 cuts from a brand new armature more or less. If you run your motors into the ground, you will have to take more off each time and may only get 3 or 4 cuts.
The proper care and maintenance of a motor is key to getting maximum life and performance.