Hi I have just tried setting the step active to low as suggested on the first page and ran my Harley Davidson plaque twice. This time the bit was above the work piece by 1.5mm. The second time it was 1.25mm above the work piece with no changes between each run. This has been the most consistent each time I have run the job. In the past it has been as high as 3.6mm above the work piece. If I set the direction to low it changes it so that up is down and down is up so I have left the low setting off on the direction for the time being. The suggestion of just moving 2 axis to see if the third axis moves is one of the first things I tried when I first built the machine and there was no movement. It also does not make a difference if the spindle is on or not.

I would welcome any other suggestions to try to solve this problem

cheers neil