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Keyboard Builders' Digest / Inspiration


Alex is working on his Theseus75, a 75% split mechanical keyboard kit with USB hub and LEMO interconnection.
Published June 20, 2023
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The Theseus75, a 75% split mechanical keyboard kit by Alex Havermale aka haversnail will come, among other interesting features, with a USB hub and LEMO interconnection.

(Yep, this is a IC/GB – extraordinary times without Reddit call for extraordinary measures.)

For the PCB design Alex teamed up with Moritz "ebastler" Plattner (whose name might be familiar as the creator of the Osprey). This particular project has been around since last October, but it has evolved a lot and deviated from the original idea considerably, thus the name refers to the Ship of Theseus problem, a thought experiment often quoted in this hobby:

When I started this project, it was intended to be a humble hand-wired split with a wooden case – however once I started sharing the design with some of my peers in the hobby, they recommended opening an IC. From there it took on a life of its own, and since then it's evolved into a pretty ambitious board. […] The name for this board was born out of the many times I've started this project over from scratch: rebuild after rebuild, was it still the same board I started with? Figured I'd leave that one to the philosophers – Alex.

Pic: SLA printed Theseus75 prototype

SLA printed Theseus75 prototype

In a quest for his "endgame", Alex was inspired by several boards already on the market, and the Theseus75 is his attempt to assemble all the features he liked into the form of a high-end, the function of a 75%, and the flexibility of a split keyboard.

My very first splurge board (though my definition of "splurge" has changed wildly over the years) was the GMMK Pro, so the 75% layout has always felt natural to me. I've always been a sucker for the U-80 aesthetic, so smooth boards with thick bezels (like the Paragon) also caught my eye. Similarly, I drew from the KL-90 for layout, the Sinc for split hot-swap, and the Mammoth75 for that marbly sound – each has offered a little inspiration in some form or another.

Pic: Milled Theseus75 prototype

Milled Theseus75 prototype

The original plan was to make the case by hand out of hardwood, but after diving further into the keyboard atelier rabbit hole, finding the right materials and manufacturers to mill such a complex piece out of wood just hasn't been tenable. After modeling and rendering an aluminum frame with several color finishes, the project lives on as a CNC milled aluminum board.


  • 6° typing angle
  • 20mm front height (~36.6mm overall height)
  • Exploded navigation + macro column
  • Two Alps EC11 rotary encoders w/ 1.5mm push-button switch
  • Magnetic interlocking
  • LEMO-compatible 1B 5-pin interconnect
  • Embedded USB 2.0 hub (useful for Yubikey, Logi Receiver, etc.)
  • Custom USB-C daughterboards (uDB S1 form factor)
  • ANSI hot-swap or ANSI/ISO solder PCB
  • RGB Underglow
  • QMK/VIA compatibility
  • Gasket mount design
  • 6063 aluminum frame
  • Frosted polycarbonate base

Alex is excited about two things specifically:

  • It's a split design with integrated USB 2.0 hubs, so that the "spare" USB port not connected to the host can actually be used as a downstream data port (@ebastler has put a lot of thought into the PCB design so that everything meets specs and most edge-cases are accounted for.) The team plans on open-sourcing the architecture after the run is completed.
  • For the interconnect, Alex decided on panel-mount LEMO connectors (after experimenting with GX-16s earlier on in the design). – "By nature, a connector like that doesn't come without its challenges, but I couldn't get over how it looked sitting on the back of the board!"

Pic: LEMO connector of the Theseus75 CNC prototype

LEMO connector of the Theseus75 CNC prototype

Since the project has been around for months, I was curious about the progress:

Are there any updates you could share?

I try to publish monthly updates on my Discord server, though to be fair I missed last month – but after several weeks of work, I'm excited to share that the first PCB prototypes just finished production! Integrating spec-compliant USB hubs into a split board has been no small task, so I want to give Moritz (@ebastler) a huge shout-out for his meticulous work.

What are you working on right now?

Since I'm currently waiting on the next batch of prototypes from the manufacturer, I've been continuing vendor and content-creator outreach as I fine-tune things like fitment and alignment. I haven't committed to any public timeline or launch date just yet, as I'd much rather underpromise and overdeliver – but my goal has been to keep the gears turning so that there's a continuous stream of updates to share with the community. As a web developer by day, I've also been working on a little project page in the interim, so I'm very much looking forward to sharing once it's complete. :)

More info

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Published on Tue 20th Jun 2023. Featured in KBD #125.



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