Gear Galaxy

A galaxy you spin with one finger.

Four black spiral arms. 20 brass gears streaming in toward a glowing orange core. Scroll, and fly in.

Falling toward the core

From out here it looks like any spiral galaxy: four arms of light wound round a warm, bright middle. Keep going. The closer you get, the more the stars start to look like teeth.

Four arms, one core

Brass gears ride four black spiral arms in toward a translucent orange core. None of them is there for show. Every one turns.

Push the rim

The knurled black bezel is your handle, cut with 120 fine grooves for a fingertip. Nudge it and all four arms swing round the stem's axle together, like a Ferris wheel.

A sun that never moves

Hidden behind the bezel is a 32-tooth sun gear, locked to the stem. As each arm sweeps past it, the 12-tooth gear at the arm's root has to roll around the sun, so it spins.

Faster toward the core

Each root gear drives five brass gears along its arm, 12 teeth near the core up to 22 at the tip. Neighbours turn opposite ways, and the small ones race: for every turn of the arms the 12-tooth gear turns 2.67 times, the 22-tooth gear 1.45. It reads as matter speeding up as it falls in.

The core turns back

A second, 16-tooth layer on each root gear drives the free 28-tooth center wheel over the orange disc. It turns against the arms, 0.52 of a turn backwards for every turn they make.

One push does all of it

No motor, no spring, no batteries. The galaxy coasts on your push while the gears work out the rest.

Gear Galaxy on its round black pedestal: brass gears spiral out from a black hub with an orange center, held up on a slim black stem.

Touchdown

Then you land back on your desk.

The whole galaxy stands 8.5 inches tall on a round black pedestal, held out on a slim stem so the wheel seems to float. It is small enough to sit beside a keyboard, and every gear in it still turns.

Orbit view

Ride along one arm

Sit on an arm and this is the view. The sun behind the bezel seems to slide backwards, and the chain answers it one gear at a time. Every mesh flips the direction. Teeth that touch move at the same speed, so a gear with fewer teeth has to turn more often to keep up.

That is why the inner gears whirl and the big tip gears stroll.

One arm seen riding along with it: the fixed sun turns backwards past the root gear, and each gear in the chain turns the opposite way to its neighbour, the small ones fastest. 32 12 12 13 15 18 22

Turns for each turn of the arm, read from the core out

  1. Root gear, 12 teeth2.67
  2. 12 teeth2.67
  3. 13 teeth2.46
  4. 15 teeth2.13
  5. 18 teeth1.78
  6. 22 teeth1.45
Gear Galaxy from the side: the gear wheel stands out in front of a slim black stem above a round black pedestal ringed with a brass line.

Built for the desk

Made to sit on a desk and be touched

Printed in three colors: matte black for the arms, rim and stand, brass gold for the gears, translucent orange for the core. A low round pedestal carries a brass inlay line. From it rises a slim stem that holds the galaxy out in front, so the wheel seems to float.

Every gear was checked in a motion simulation to mesh and turn through a full revolution, 29 of 29 conditions clear, with no part clashing with another. All 21 printed part designs pass the wall-thickness and support-free overhang checks for a 0.4 mm nozzle.

Flight manifest

Gear Galaxy

Size
6.1 × 6.1 × 8.5 in
Weight
8.0 oz
Colors
Matte black, brass gold, translucent orange
Gears
20 brass chain gears on 4 arms, 4 two-layer root gears, a fixed 32-tooth sun and a free 28-tooth center wheel
Power
Your finger. No motor, spring or batteries.
Made
3D-printed from 21 part designs, gear teeth at a 1.5 mm module