Summary

Introducing Apex—an entrancing 3D printed marble machine. Watch the marbles carefully as the spiral lifts them up, and they weave down a plinko board, stairs, and various other tracks.

The machine uses 8mm or 5/16" marbles (the distinction is negligible), but can be scaled up proportionally to use larger marbles.

Video: https://www.youtube.com/watch?v=76Xtjbtv-K8

If you like marble machines, check out some of my other work!
https://elegantmachines.etsy.com

Dimensions:
-Length: 6.75" (170mm)
-Width: 5.75" (150mm)
-Height: 5.5" (140mm)

*Please ensure ball bearings are out of reach for children under 5, as they present a potential choking hazard. 

Print settings

No supports are required for any of the four main files (everything except the crank). A layer height of around 0.16mm (or 0.2mm) is recommended, at least for the main machine. A printer bed size of at least 170mm x 170mm X 140mm is needed. The crank is another, optional, way to spin the marble machine, and does require supports to print.

The story

I designed this machine over the summer of 2023. Surprisingly, the failure rate (number of marbles that fell out or jammed / number of marbles cycled) was only 0.4% for the first version of the design--not bad! I raised a few walls, added a few supports, and made the track steeper in a few places; the second iteration had a much better failure rate of 0.06%. Still, that wasn't up to my standards (below 0.02%). Fortunately, the third version did meet standards; it had no failures after cycling 20,000 marbles. Still, I didn't stop there. Since then, I've optimized the design further, cutting out unnecessary supports, reducing filament usage, and reinforcing various sections. As of December 2023, I'm on the eighth version of this design, and I still have ideas for micro-optimizing it.