These are loose 3/8″ Chromed Carbon-steel G40 bearings. These are not in a bearing-race. Think of these like “Steely” marbles when you were a kid (many, many moons ago).

We use these in our Marble Machine Kits, and as magnetic swivel points on our CarouSol “Squid Hunting” kit

3/8″ (0.375″) diameter (9.525mm)
3.6g each
LOTS OF 10. Buy 1 means you get a pack of 10 balls!
Grade 40

The Solderless Solar version of the Marble Machine brings the same tick-tock pulse movement but with none of the molten metal! The only tools required to get this beauty running is a phillips-head screwdriver, some glue, and a bit of elbow grease.

Our Solarengine circuit stores the light from the solar cell, and releases it in an occasional pulse that drives the mechanics. In sunlight, the motor will pulse every few seconds, and drop a ball every half minute. In indoor light, motor pulses decrease to every few minutes (be patient). But you can always use the hand crank to manually advance the marble wheel.

Features:

Easy to build, with engraved building notes
Solar-powered or hand-crank operation
Operates in indoor light!
3/8″ steel balls

Each kit includes:

1 x Set of laser-cut Fiberboard parts
1 x GM9 motor
2 x #4x½” screws
7 x 3/8″ steel Balls
1 x Double-sided sticky tape
2 x 2-conductor wire
1 x Solar Engine circuit board

The Solderless Solar version of the Gravitrack marble machine brings the same tick-tock pulse movement but with none of the molten metal! The only tools required to get this beauty running is a phillips-head screwdriver, a sharp edge, and a bit of elbow grease.

Watch as the sun powers the slow but elegant hand-off mechanism that passes marbles to the top of a sweeping multi-level track. You will witness the fascinating step-by-step action of the arms as the geometry changes periodically. Patience is rewarded with the plunk, and rollll of a successful motion cycle. The more light it gets, the more often it moves. It’s solar-powered stop-action motion!

Specifications:

Intermediate skill level – ages 14+
Soldering NOT required
Basic hand tools required (Phillips screwdriver, craft knife, wood glue)
No batteries included (or needed – it’s solar powered!)
2 hour build time

Kit includes:

1 x Set of laser-cut wood parts
1 x GM3 Motor
1 x 37x66mm solar cell
1 x Solderless SolarEngine board
1 x GMW Motor mount
4 x 3/8″ steel marbles
Assembly hardware

See the GraviTrack Battery

We’re pleased to carry eSun 3D printer filament. Excellent quality, vacuum packed, and on an easy-to-view transparent spool.

eSun is a top supplier of 3D printer filament, and we’re happy to be carrying their inventory. They are not some fly-by-night operation; eSun is an active part of the 3D printer community, and you’ll often see them represented at Maker Faires and 3D Printer Expos. We’ve even been to their labs at the Shenzhen University grounds where they develop and test their product. They take excellent care with their production methods, and each spool comes vacuum sealed in a pouch with moisture-absorbing desiccant. In short, eSun knows their stuff. We’re extremely happy with the quality and consistency of their material.

Features:

Like regular PLA, it is still 100% biodegradeable.
A Marble stone-like appearance

Specifications:

Base chemistry: polylactic acid biodegradable thermoplastic
1.75mm nominal diameter (spec’d +/- 0.05, but is in practice closer to +/- 0.03)
1kg spools on transparent LARGE diameter (easy unspooling) reels, vacuum sealed with desiccant
Suggested build parameters:
- Print temperature 190-210℃
- Base temperature: 0/65 °C
- Feed speed: 30-90mm/s
- Idling speed: 90-150mm/s

If you loved your battery powered Marble Machine but feel that it’s missing a little solar flare, use this parts bundle to convert it!

Bundle includes:

1x CP4700uF
1x CP0.47uF
1x TR2222
1x MCP112-270
1x D1
1x SCC3733
1x KMSE PCB
1x SWire 7″
1x DSST

The Solar version pulse-moves the elegant hand-off mechanism that passes marbles to the top of a sweeping multi-level track. You will witness the fascinating step-by-step action of the arms as the geometry changes periodically. Patience is rewarded with the plunk, and rollll of a successful motion cycle. The more light it gets, the more often it moves. It’s solar-powered stop-action motion!

Specifications:

Intermediate skill level – ages 12+
Soldering required
Basic hand tools required (Phillips screwdriver, craft knife, wood glue)
Soldering tools required
No batteries included (or needed – it’s solar powered!)
3 hour build time

Kit includes:

1 x Set of laser-cut wood parts
1 x GM3 Motor
1 x 37x66mm solar cell
SolarEngine circuit board & components
1 x GMW Motor mount
4 x 3/8″ steel marbles
Assembly hardware

See the GraviTrack Battery

Elegant, swooping hands pass marbles to each other to the top of a sweeping multi-level track. A switched battery pack smoothly exercises the mechanism. The smooth pick/hand-off/place motion is hypnotic and enchanting. No soldering is necessary.

Measuring approximately twice as wide as our original Solar or Battery Marble machine kits (at 250 x 127 x 140mm, or 10″ x 5″ x 5.5″), the GraviTrack is still desk-top compact but large enough for easy mechanical assembly.

Specifications:

Beginner skill level – ages 12+
Basic hand tools required (Phillips screwdriver, craft knife, wood glue)
2 x AAA batteries required (not included)
2 hour build time

Kit includes:

1 x Set of laser-cut wood parts
1 x GM3 Motor + battery pack
1 x GMW Motor mount
4 x 3/8″ steel marbles
Assembly hardware

See the GraviTrack Solar

You are probably familiar with its older cousin, the Solar Marble Machine that has a clever circuit that delivers short bursts of energy collected by the solar cell to the gear wheel.

The battery pack edition of the Marble Machine kit has splendid electromechanical appeal, delivering 8 steel balls down a laser-cut fiberboard frame. Unlike its solar-powered cousin, it’s ready to run at your command.

Features:

Securely tucked under the return rail, the battery pack provides hours of power to rotate the gear wheel that brings the marbles up to the top of the spiral.
No-solder battery-powered construction.
Precision laser-cut fiberboard frame.
All electronic and structure parts included.
2 x AAA batteries required (not included – get them here)
Basic tools required (no soldering)
1 hour build time

The Marble Machine in Action

The Marble Machine assembly video:

Here’s the new video of the complete Marble Machine in action:

We’ve been big fans of Mr. Raynsford (of “Just Add Sharks”) and his work since he started the 365 lasercut projects in 365 days challenge. One of the projects featured there was the marble machine, something we really thought was a cool project, and so we worked with him to bring you the Solarbotics edition – solar powered!

This kit requires basic soldering tools (soldering iron, solder), a Phillips #1 screwdriver, and a small amount of white glue.

Features:

Easy to build, with engraved building notes
Solar-powered or hand-crank operation
Operates in indoor light!
3/8″ steel balls

Each kit includes:

1 x Set of laser-cut Fiberboard parts
1 x GM9 motor
2 x #4x½” screws
7 x 3/8″ steel Balls
1 x 4700µF capacitor
1 x SCC3733 Solar Cell
1 x PN2222A transistor
1 x MCP112 trigger
1 x Double-sided sticky tape
1 x 0.47µF capacitor
2 x 2-conductor wire
1 x Diode
1 x Solar Engine circuit board

Final assembly – wooden frame:

Our GraviTrack Marble Machine Kit is our newest addition to the Marble-Drop mechanism family. Elegant, swooping hands pass marbles to each other to the top of a sweeping multi-level track, available in either solar or battery configuration!

Approximately twice as wide as our spiral Solar or Battery Marble machine kits, the GraviTrack is still desk-top compact but large enough for easy mechanical assembly.

Pre-order yours here: Solar Edition & Battery Edition

Click here for full feature list on Solar Edition GraviTrack

Click here for full feature list on Battery Edition GraviTrack