I use a Frankford prep station but saw this 3D pattern recently and decided to build one just for kicks and giggles. After a couple days of tinkering with individual parts sizing I finally got it working pretty smoothly. I used $3.50 worth of nuts and bolts from Ace, a high torque motor from Amazon (~$13.50) and a PWM motor speed controller from Amazon (also about $13.50). Bits I already had, skateboard bearings, 12v 2A power supply, power jack as those are all lego parts that I keep around for projects just like this. The bulk of the parts are 3D printed though.
https://www.theoutdoorstrader.com/threads/brass-prep-station-3d-printed.2427477/#post-11150770
https://www.theoutdoorstrader.com/threads/brass-prep-station-3d-printed.2427477/#post-11150770
