[zukes3140]

I have just purchased a Bridgeport EZ-TRACK DX2 S/N 8251-E and I am trying to cut a circle 10 in. in Dia. I have installed the X&Y backlash comps and I cannot cut a good circle. I also bought new ball screws and nuts. I ploted a polar chart of the circle every 15 degrees. On the X-axis Plus and X-axis Minus the circle looks good until it gets to the y-Axis at 105 degrees Plus, and 270 degrees Minus. The circle deviates about .005 from the perfect circle. At 105 degres the circle deviates plus .003 from the perfict circle, then jumps to minus .002 at 90 degrees. At 285 degrees the circle will deviate, plus .001 from the true circle and jumps to minus .004 at 270 degrees. Talk to me like a six year old; because, this is my first CNC Machine.