3D Printed Marble Machine

Summary

The 3D Printed Marble Machine is a compact, hand-held marble machine designed to fit in one hand and hang on a Christmas tree. Created in the episode "This 3D Printed Marble Machine Fits in your Hand," the project was completed in four days before Christmas and released as fully open-source. The machine uses a small motor behind a gear mechanism to lift clear spheres (marbles) to the top using magnets, then releases them to roll back down in a continuous loop. The project highlights the accessibility of 3D printing and encourages makers to create their own versions using readily available components and shared design files on MakerWorld.

The build drew inspiration from marble machine creators Ivan Miranda, Engineezy, and Wintergatan. The core mechanism is described as: "here's the basic design I can't make it much better a small motor behind spins the gear lifts them up when they get to the top lets them go and they drop."

Design

The primary design constraint was creating a marble machine that could be printed without supports, a challenge that shaped every iteration of the project. The host worked in Fusion 360 to model the concept, starting with initial sketches before moving to CAD. The design objective was to create a marble machine that was portable, easy to assemble, and fully open-source.

The machine operates through a simple mechanism: a small motor drives a gear that carries magnets. As the gear rotates, the magnets attract clear spheres and lift them to the top of the device. At the peak, the marbles release from the magnetic field and roll back down to the bottom, where the cycle repeats. The compact size was essential to the design goal of fitting in one hand and serving as a Christmas tree ornament.

The bill of materials was deliberately minimal: "for this you'll need magnets 3D printers a bunch of Steel Balls some screws a small motor and the hardest of all found these small clearer spheres." The choice of clear acrylic spheres over steel balls for the visible marbles was described as "the trickiest part" of the sourcing process.

The initial concept envisioned a sphere shape, which was believed to be aesthetically pleasing and mechanically sound. However, this spherical design proved incompatible with the no-supports printing constraint, as internal geometry required support structures that would be impossible to remove from a closed form.

What Failed

The spherical design suffered repeated print failures. The core problem was geometric: a sphere-shaped marble machine required internal features that could not be printed without support material, and once the sphere was closed, those supports became permanently trapped inside. As noted: "it's still missing a piece that I'm working on now it's the trickiest part he hasn't figured out how to print it at once no supports in between one print fail two print fail three print fail same routine."

Multiple attempts to print the spherical version all failed for this reason, forcing a fundamental redesign.

Iterations

This 3D Printed Marble Machine Fits in your Hand

After the repeated failures of the spherical design, the host reconsidered the fundamental shape. "Then he had a new thought a new shape he could see of course he said make it the shape of a tree so we changed the design from a spier to a cone hoping this time each part stood alone."

The cone (Christmas tree) shape solved the support problem by opening up the internal geometry. Where the sphere had trapped internal features, the cone's tapered form allowed each part to stand independently during printing and meant that features could be oriented to print without needing support material, or any necessary supports could be easily accessed and removed. The result was successful: "the supports were removed much easier this time this came out perfect it's much more refined."

This final iteration successfully printed without internal supports, assembled cleanly, and operated as intended. The motorized gear lifted the marbles magnetically, released them at the top, and allowed them to roll back down in a continuous loop, all while maintaining the Christmas tree ornament form factor. The complete redesign and successful build were completed within the four-day deadline before Christmas.

Outcome

The final build succeeded in meeting all design goals: it fits in one hand, hangs on a Christmas tree, prints without supports, and operates as a functional marble machine. The project was completed within the four-day deadline before Christmas and all design files were released as open-source on MakerWorld, making the design accessible to anyone with a 3D printer.

The simplified build process encourages creativity and experimentation among fellow makers. The creator expressed satisfaction with the final product and indicated a willingness to engage with the audience in sharing their designs, thus fostering community involvement.

For further exploration of this project, you can visit the link provided to access the 3D print files. For more information, visit the creator's Patreon and consider subscribing to their YouTube channel for updates on future projects.

Parts & Tools

The following components and tools were utilized in the construction of the 3D Printed Marble Machine:

Components:

small motor - to power the lifting mechanism
magnets - used to assist in lifting the marbles
Clear spheres - functioning marbles in the machine (described as the hardest to source)
Steel balls - alternative marble option
screws - for assembly connections
3D printed parts - cone/tree-shaped housing and internal mechanism

Tools:

Fusion 360 - for design modeling
3D Printer - for fabrication

Distribution:

MakerWorld - design file hosting