How to build K-Scale K-Bot
20-DoF humanoid robot · Expert
K-Bot is K-Scale Labs' open full-size humanoid: 20 Robstride actuators on a 48 V CAN bus, Onshape CAD, and a kos/ksim software stack.
Research-grade: machining, motor drivers and control theory.
Our estimate, part-time
Price the BOM yourself
CERN-OHL-S-2.0
What is K-Scale K-Bot?
K-Bot was K-Scale Labs' attempt at an affordable, full-size open humanoid built from commercial parts. It uses 20 Robstride quasi-direct-drive actuators on a 48 V CAN bus and was designed to be repaired: hands swap through a lens-style mount, and the head comes off.
K-Scale shut down in November 2025 and refunded preorders, so there's no dev kit to buy. The repositories are still public, with the Onshape CAD, electrical docs and software split into submodules for the operating system (kos-kbot), simulation (ksim-kbot) and inference.
Treat it as a documented reference design. Building one means sourcing actuators and fabricating CNC parts yourself.
K-Scale K-Bot specifications
- DoF
- 20
- Actuators
- Robstride RS00 ×2, RS02 ×6, RS03 ×8, RS04 ×4
- Bus
- 48 V power + CAN
- Battery
- 12 Ah NCM pack with BMS
- CAD
- Onshape
Figures as published by the project. See Sources below.
Bill of materials
| Part | Qty | Notes |
|---|---|---|
| Robstride RS04 (40 Nm rated) | 4 | |
| Robstride RS03 (20 Nm rated) | 8 | |
| Robstride RS02 (6 Nm rated) | 6 | |
| Robstride RS00 (5 Nm rated) | 2 | |
| Fabricated torso, arm, leg, head and battery-enclosure parts | — | From the docs' part lists |
| 12 Ah NCM battery with BMS and powerboard | — |
Where's the full bill of materials?
The full BOM, with exact quantities and vendors, lives in the project's own files. Prices change often, so treat Not published as a ballpark. Start at the project repository.
Tools you'll need
- CNC fabrication access
- USB-CAN adapter
- Torque drivers
Step-by-step build overview
Electronics & wiring overview
A fused 80 A main connector feeds the powerboard, which distributes 48 V and CAN to each limb. The robot shows up to the host largely as one USB device.
Software
The project ships its own firmware and control code. See the repository for setup.
kos-kbot (robot OS), ksim-kbot (simulation and RL) and kbot-inference, all in submodules of the main repo.
Tips from the bench
- ☕ The company is gone, so community forks and Discord archives are your support.
- ☕ Simulate everything before powering a full-size robot.
K-Scale K-Bot FAQ
Can I still buy a K-Bot?
No. K-Scale Labs shut down in November 2025; only the open files remain.
What actuators does it use?
Twenty Robstride units across four sizes, from RS00 to RS04.
Sources
Written by Bots n' Beans from the project's own documentation. Check the sources for the latest revision before you buy parts.
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