Need to catch up on software updates - hey! Thanks for your reply. What happened was, the first time I run the post processor, all the Z values were along 2mm (about 0.080") too far, destroying the workpiece. Has never happened to me before and 99% sure I did it the same as I always have. Seems strange and having trouble getting my head around how it could have happened. Never changed the toolpath and run the post processor a second time and the CNC program was then correct.

Have been using the 'mplfan.pst' mastercam post-processor with lathe version 9.1 since day dot. Had size problem on job and found when I post-processed toolpath a second time, I come up with with a different result. Me or Machine?