FASTER Mini-Marble Run - Handheld, Two Tracks, One Easy Print

Easy to print in one piece.

This is a faster version of my hand-held, portable marble run. Turn the outside wheel to lift the bearings to the top of the tracks.  They’ll pop out and run to bottom where they re-enter the outside wheel to start the next cycle.

This version has steeper inclines so the marbles travel much faster down the track, and you don't need to be as precise holding it straight up and down.

It is tactilely and audibly satisfying. As the balls enter and exit the tracks, they make a “click-click” you can hear and feel.

It prints easily as one piece. The only assembly is to press 5mm ball bearings into the tracks.

I’ve included two versions of the model:

• Tight clearances - Should work on most newer printers and old ones if they are well-calibrated.

• Loose clearances - Should work with all printers, but may leave enough space for marbles to hang up between the rings.

It takes about 2 hours on modern Core-XY printers.  4.5 hours on modern bed slingers. 6-8 hours on very old printers.

You can print it using one color, or set your slicer to do filament changes at various layers to get cool effects. 

Once you print it out, you can press the bearings into the two tracks.  I recommend using about 8 per track.

Any 5mm bearing should work.  Here are the ones I used: https://www.amazon.com/dp/B0FDVZXY6Z (Not an affiliate link).

Just set the bearing on the track, then press it in with your thumb.

Then hold it upright by the thumb grip, turn the outer wheel and enjoy!

Note: To operate correctly, the model should be held with the thumb grip on the left side (See photo below). If you hold it with the thumb grip on the right, it will be upside down and the marbles may get hung up a little inside and prevent smooth ring rotation.  (The internal top part of the ring is different than the bottom.)

I’d love to hear feedback, and ideas for improvements or other variations!