Hi,

After having several weeks of randomly scrapping parts with erratic diameter errors I've finally had time to try and sort out our problem. Here's what's been done so far.

Changed the x-axis servo motor (was suggested by service engineer that the motor may have lost it's magnetism).
Changed the x-axis bearings and had the ball-screw refurbished.
Checked for any play in the trucks (x & z axis), both have less than 10 micron in all directions (it is an old machine).

I had checked for any turret movement from turret body to turret disc and at the time got almost no movement. The machine will cut good parts and then scrap parts randomly although the problem now is pretty consistent. So here's what I've now found.

Placing a clock to measure radial movement of the turret disc relative to the turret body I can get +/- 0.1mm movement using a 2ft bar in a turning tool pocket.
Using the same method as above placing a clock on the back face of the turret disc the face is moving away from the turret body 0.04mm (I think its climbing up the taper faces of the coupling here?)
Clocking off the chuck face to measure x-axis movement I get +/- 0.04mm just using my own weedy strength!

Any ideas anyone?