Re: Bridgeport 1000 vmc retrofit with y axis surface finish issues
Some radial movement in the ball screw is OK. The axial movement is what you are most interested in. Based on your measurements it looks like the ball screw/nut is not too bad. In a perfect world, the axial play in the ball screw would be 0 under any normal operating condition. The ball nut should be preloaded for 0 axial play.
The real measurement needs to be taken with the machine assembled and look at the table movement with the ball screws locked. Not locked with the servos, but rather mechanically locked with a clamp of some kind to prevent any rotation. Then it's just a matter of tracking down where any movement is coming from. Could be the ball nut, or thrust bearings.
Jim Dawson
Sandy, Oregon, USA