[Geof]

..... Do you think this will also induce the same amount of relieval of distortion to allow it to go out of tolerance??

That I cannot answer directly. My experience has been working with flat material and I found it was best to approach the final size by many small passes rather than hogging 90% off with a single roughing cut.

Have you experimented by taking many small cuts with the CNC to replicate as close as possible the way you did them in the manual machine?


Also, but not directly related to the distortion issue, how are you doing the roughing in the CNC. With a boring tool or by interpolation? Obviously on the manual machine everything must have been boring. Have you ever tried plunge milling? It is possible you could reduce your roughing cycle time.