I have an Ammco 8500H at the shop. Years ago I made a 16 1/2" standard to check our drums. A 2 mm bit is used for a go or no go and that gets us pretty close to the .080 allowable oversize to reused. I'm not sure I have anyone working for me that can read the mike anyway. We chuck up new drums on a lathe and check for runout and occasionally have to cut a new Gunite made in USA drum.