Hi wh,
Just a thought, and with a bit of lateral thinking on this topic for operating a rotary axis in linear mode.
If you were to calculate the steps per one revolution of a rotary axis and divide the answer by pi and then enter the result into the ‘steps per’ for the A axis - it would then have the correct linear movement on the surface of a 1 inch diameter cylinder (fitted into the A axis).
Using Screen4 (or Screen Designer) add the A Axis Scale DRO (OEM62) and LED (OEM44) which for some reason have been removed.
Now for any diameter of work fitted in the A axis, perform the calculation 1/diameter and enter the result into the A Axis DRO.
Then the linear movement on the surface of the work will be correct for that diameter.
I have not actually tried this but I will do.
Tweakie.