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Planetary gear set

A sun gear, planets and a ring gear that mesh around each other, with a carrier for the planet pins. Big reductions in a small, flat package.

  • 1.05 x 1.06 in

    Shown in Delrin (acetal), .125 in

    Sun gear, 15 teethx1

  • 1.05 x 1.06 in

    Shown in Delrin (acetal), .125 in

    Planet gear, 15 teethx3

  • 3.72 x 3.72 in

    Shown in Delrin (acetal), .125 in

    Ring gear, 45 teethx1

  • 2.56 x 2.56 in

    Shown in Delrin (acetal), .125 in

    Carrierx1

All templates
Ring teeth
45
Ratio, ring held
4 : 1
Planet pin circle
1.875 in
Gears
in

Pitch diameter divided by teeth, the same on every gear in the set.

Bores
in

0 for no bore.

in

For the pins the planets turn on. 0 for no bore.

Ring
in

Solid material outside the ring's tooth roots.

in

A plate with a pin hole for each planet.

With the ring held still, turning the sun turns the carrier slower by the ratio shown. Each planet drops in at whatever angle meshes with both the sun and the ring; turn it a little until it does.