Controller board and firmware for polar cnc mill

Hey guys, this is my first post, and inevitabely kind of a shot in the dark.
There is a dental style "chairside" CNC mill for sale in my area. See link for some info:

https://www.machinedesign.com/mechan...-dental-crowns

The machine has an envelope of 40x40x40mm, and obviously I wouldn't be machining much dental crowns with it [emoji846]

The challenge I have on hand is that the machine has 3 polar axes and 1 cartesian, and I would need a firmware which can handle this. Next challenge would be me learning to tweak the firmware to work...

I am wondering which firmware and controller combo would be best suited for this mill? The servos have external drivers with normal step/direction inputs, which at least doesn't over complicate things.

I found this link, explaining how Duet can be set up with polar coordinates, which in turn led me to this forum:
https://duet3d.dozuki.com/Wiki/Confi...rePolarPrinter

The tutorial leads you through how to set up one axis as a polar axis, but will the firmware handle 3? Plus 1 cartesian?

The printer comes with a Delta Tau Clipper controller board, but the license for this alone is as expensive as the mill, so that is kind of out of the question...

ANY help at all would be really appreciated.

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