Someone asked. I forget who. Here is a good candidate stepper to fit on an mm1.
thinking you take the gear off and solder or other on proper 80 pitch threaded rod. Then you just need a slit and spring to let the motor turn but not turn itself. Tap in two more rods and 3D print a holder. Use a spring to hold it tight. Might have some backlash so design a better mount idea. Other idea is glue piece of tubing that fits on the existing knob on the mm1 to the gear. Now it can slip if you go too far. You can try flex shafts too. I have not found any yet.
The programming of this is off the shelf. Buy a stepper tester. Might cost 10.00 for each mm1. Accuracy unknown.
https://www.ebay.com/itm/38374679442...Cclp%3A2047675
this one I think has the right screw
https://www.ebay.com/itm/38380554903...Cclp%3A2047675