Quick video, just milling a mounting bracket for the motor shaft.  Rather than a grub screw, the d-shaft is sandwiched between two plates, and the whole thing screwed down to a 2x4 for testing.  A cheap EST and PWM servo tester later, and the patcher is moving on it's own volition!

The ESC is under-rated and insufficient (it's just a cheapo ESC that I had laying around).  Spec'ed at only 14v (4s lipo) the motor is too slow.  Overvolting to 20v speeds it up a bit closer to realistic RPM, but the ESC grows very hot.  In reality the motor would prefer 30-48v, so I need to get a larger ESC for actual usage.

The PWM generator is just a simple servo tester, and will eventually be embedded in a foot pedal.

Finally, the patcher really needs a belt tensioner.  I tensioned by just applying force and screwing down to the 2x4, but as you can see in the video there is a fair amount of play in the belt (in addition to the runout *cough*).  When I make a proper stand for this, I'll include a belt tensioning mechanism.  Probably just some kind of swivel for the motor mount, allow it to be pulled tight.  Or potentially a spring-loaded pulley similar to how cars tension belts.