Conical Spiral
19 Jan 2026 | by Marta
A simple yet highly eye-pleasing conical spiral designed for 0.5" (12.7 mm) steel bearings. ๐โจ
๐ ๏ธ Project Details
- Ball Size: 12.7 mm (0.5 inch) marbles.
- STL file
- Onshape model

This track features 3 full rotations where the marble descends gracefully. The geometry is designed so the ball gradually slows down as it reaches the bottom, thanks to the decreasing slopeโcreating a very satisfying visual effect! ๐๏ธโก๏ธ๐
๐ฅ Built-in Storage Case Tired of losing your bearings? The center of the cone features a built-in reservoir (container). Once the marbles finish their run, they collect safely in the middle. When you're done playing, you can easily pour them out! ๐ก๏ธ๐
Ideas
- Physics: Variable slope for a "gradual braking" effect.
- Storage: Integrated center pocket to keep your marbles from rolling off the table.
- Aesthetics: Minimalist conical design that looks great on a desk.