I've been meaning to post an update for 3 weeks now, but I couldn't seem to get around to do it.
I received the last plywood sheets a month ago and I could finally finish my keyboard. I used a 5mm sheet to frame the circuitry and a 2mm sheet for the closing bottom layer. It leaves a tiny gap as the Pro Micro with the wires coming out of it is about 5.5mm thick so 5mm is just not enough, but in the end, the gap is actually useful because it allows me to check whether I plugged the keyboard in correctly.
I'm really happy with the way I cut the 5mm frame. I had been wondering how to do it for a long time. I didn't want to have to glue separate pieces of frame to make openings for the USB and TRS plugs but I didn't see how I could do it in one single piece. It was another fablab member who gave me the idea of going around the components. I engraved a line to delimit parts I would have to carve to let the TRS wires through as well as the micro USB breakout board. I then chipped the wood with a cutter. The laser cutter slows down and engraves deeper when reaching the end of a line when you don't calibrate it properly. That's why the wood appears to be cut all the way through on both sides of the micro USB plug. In retrospect, I think I should have calibrated the laser cutter to make a 2mm deep surface engraving, it would've been cleaner.
There it is, sitting at my desk:
After a week of carrying it to work and back, I started to get annoyed at keycaps falling off, or worse, keycaps being pushed in too deep. Apart from sitting lower than the other keycaps, which is uncomfortable, they are almost impossible to pull out. I when trying to pull them out, the switches themselves would pop out of their hole and I would end up pulling on the wires... Not good. So I made lids:
Two frames of 5mm plywood and a 2mm top cover. I extended the frame 1mm towards the center, and surface engraved the entire surface except from those 1mm. That way, the raised edge it leaves fits snugly inside the frame around the keycaps. When I put the lids on, they kind of click into place and won't budge when pushed sideways. They fall off if you turn the keyboard upside down, but so far I they never fell off while I was carrying them in my bag. No more pushed in caps!
I have been using my keyboard for a month, now, and I takes a bit of getting used to it. Some keys somehow appear a lot closer than before, so I tend to press the next key. It happens a lot when I want to press the letter I and end up pressing Enter. My thumbs are still in the process of getting used to deal with so many keys, but I'm doing better and better. Overall I'm quite happy with it. It's undeniably more comfortable than my Typematrix was, even though for the moment I mistype quite a bit. Funnily enough, the design feature that my hands adopted almost instantly was the aggressive column staggering.