Awesome Open Source
Awesome Open Source

42 Keyboard

40%, splittable, mechanical keyboard.

Project Structure

  • Build – Build log, bill of materials, tips on where to source parts, assembling tips, learning resources I used while designing this keyboard.

  • Case – Fusion 360 project and STL files for 3D printing the enclosure.

  • Firmware – QMK configuration. There is a Makefile to build and load the firmware.

  • PCB – Kicad project and Gerber files for manufacturing the circuit board.


In January 2018 I wanted a keyboard with a specific set of features. The simplest options to get that keyboard were to wait for a group-buy or build my own. Waiting time and costs for both options seemed similar, so I went with the option where I would learn the most.

Needs and knowledge changed over time, so I made different iterations to add new features and account for the lessons learned from previous builds.


  • 40% – All keys can be reached with minimal finger movement.
  • Splittable – You can split the keyboard for more comfort, or use it as one piece for better portability.
  • Hot-swappable switches – No desoldering pain if you want to try new switches.


If you have some feedback or questions, feel free to create an issue. Your input is more than welcome!


Pictures for the current version will come soon. In the meantime, you can check the previous versions.

Previous Versions

  • version 3 – PCB, QMK, Bluetooth, micro USB
    v3 picture
  • version 2 – Handwired, QMK, Bluetooth, micro USB
    v2 picture
  • version 1: PCB, Split, TMK firmware, USB C
    v1 picture
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