<robrotics/>

<actuators/>

Compact harmonic drive actuators you can print at home. Every one ships with its CAD files, a complete bill of materials, and the actual load-cell data behind the torque numbers, because a spec you can't check isn't a spec. All free under CC BY-SA 4.0.

The HD20 actuator opened up, showing the ball-cage wave generator inside the printed body.

HD20

20:1 harmonic drive · NEMA 17

Bolts onto any standard NEMA 17 stepper. Tested to 3.3 N·m, prints on a normal printer, and costs about $4 of hardware per unit.

  • 20:1 reduction
  • 3.3 N·m tested
  • ~$3.96 hardware
view the build →

more coming

bigger, smaller, and higher ratio

We're working on other sizes in the same family. Want to be told when they land, or have a size you'd actually use? Say hello on YouTube or email us.

<design-your-own/>

Every one of these starts in our free harmonic maker, a parametric tooth profile generator that exports DXF. If you'd rather understand the mechanism before you build one, start with harmonic drives, plainly.