Print emmett's "CubeGears2-3.stl". If you can edit the file, you can delete one of the large corners, the center hub, and one pin before printing as these parts are not used. Clean up any stray filament in the gear holes. See Geared Heart, Motorized Edition for the steps I performed in loosening up the geared cube as the it must spin freely.
Print all parts. While printing "Top.stl", I paused the printer at 4.2mm and changed filament from black to silver.
Test fit, file, sand, etc. for smooth operation. Lubricate the gears, "Gear Wheel Hand.stl" bushing surface and "Wheel Hand.stl" bushing surface using white lithium grease or petroleum jelly before final assembly.