Hi folks. I made this model/prop at a friend's request for visualizing/demonstrating/teaching quantum computing & qubits…

The provided STEP file contains the entire assembly. For printing, you'll need to ‘split to objects’ and re-orient some of the pieces. The hemispheres require supports. Some support on the tapered ends of the axle won't hurt. I've drawn in supports to bridge the counter-bored holes…

Non-3D-printed hardware:

• (7) M3 x 4mm heat-set inserts
• (5) M3 x 5mm bolts (4mm should work too)
• (2) M3 x 8mm (6mm should also work, these are for affixing the axle)
• (1) M3 flat washer
• (1) M3 wave washer
• Red Loctite/equivalent

You can forgo the last 3 parts if you just want a display piece… If you want the piece functional, I suggest placing the wave/flat washer between the axle and pointer and using Loctite on this bolt as well as the two that hold the axle. Adjust the bolts for proper pressure so that the parts can rotate before allowing the Loctite to cure…

Scaling: the sphere diameter (as drawn) is 170mm and the parts will fit on most print beds. If you wan something larger, I suspect you can scale up to a new fastener size, though I haven't tried that myself…

Post-processing: the overhangs/supports leave some pretty rough areas on the hemispheres… In the photographed model, I dremeled/sanded/primed/filled to clean things up--as it turns out, the primer I had was an exact color match to the gray filament I used, so I got away with just working the undersides… If you intend to do the same, I suggest bumping up the ‘bottoms’ to 5 or so so that you have some extra material to work with. I used 4 perimeters in my prints just to limit the possibility of breaking things on layer lines.

I've got some improvements/ideas, but that will be v2.0… 

Enjoy! Post your makes.