@dc42 Thank you. The math looks good. I will try it out.

In the mean time I used a couple blocks to align the part to the x and y axis and then found zero using the edges of the part. It would be great to have a macro that allows you to place the part/stock and then adjust the machine using the edges without having to do the manual alignment. Assuming you have a couple straight edges perpendicular to each other. Another handy thing would be a macro to flip the part if you need to machine both sides of the part. Is there a G code that allows you to mirror one of the WCS axis?

@punktphil looks like that's being introduced in 3.5. You'll find that as features get added to the firmware (at pre beta and beta stages), they'll get documented as it's easier to create the docs when you add features rather than remember to go back and do it.
So for the time being, you can't use K

@bigdave
How is your project coming?

I'm surprised you are using ball screws and a control without backlash compensation. Do you just need fast, without concern for precision? Is there something else drawing you to duet?

If duet had backlash comp, I'd put it on one (or more) of my desktop machines, but without it, I'm sticking with the existing LinuxCNC. I suppose one could use a Marlin or Beagle board, but I haven't used either yet, so I don't have a favorite or a reason to migrate. (Like standardization.)