I have a old CNC Bridgeport Boss 5 with a cnc conversion kit using the original motors running on Mach3. The machine runs great and very tight. The issue I am having is with x and y axis in straight lines it runs smooth but if I make a circle pocket or bore a hole the machine seems to vibrate a lot and leaves a chatter marks not smooth almost as if the motors are not tuned correctly but not sure. I am cutting cast aluminum and part is very secure so it is not a fixture issue. The machine vibrates while cutting air when doing a circle cut.