The mention of 3 phase makes me wonder. Most residential areas do not ha ve3 phase available.There are converters to change a 3 phase motor to single phase,but then would you not still get the vibration mentioned?

Doing chambering work , .001-.003 out of alignment can sure screw up a good barrel

If God wanted you to walk and carry things on your back, He would not have invented stirrups and pack saddles