Used an Up! Mini printer, with speed set to slow, and quality set to "solid". Took about 6 hours, in 3 loads.
Screwed it together using 8x1 Brass wood screws. They only need to bite into the core a turn or two.
The paint was 2 thin coats of primer, 2 coats of gold, and one clear coat of clear. After 3 days, it still smells like paint. The paint on the gears has been getting ground away, which I should have anticipated.
Without the paint, it operates very effortlessly, but when the paint was new it was tough to turn, and I thought I'd crack it.
We attempted to create 3D printed "Pins" to were superglued between the core and each gear. This was a total failure. After about 4 rotations, the first pin snapped. The rest just felt terrible, and the core had to be re-printed.
We opened up the core pilot holes using some drill bits, but ABS plastic just melts and hardens onto the bits, rendering them useless and the holes very sloppy.
Much learnt by printing this wonderful gadget out!