Recreating the Model F look and feel: the Model D is a 40% Buckling springs keyboard built by u/crahamson.
KBD.news Published June 1, 2022
No, this is not an obscure IBM model from the '80s. Model D is an amazing contemporary project shared by crahamson aka durken: a 40% ortho capacitive PCB for switches salvaged from a Model F.
It's called Model D and uses buckling spring switches from an old IBM Model F, a custom capacitive PCB and an XWhatsit capsense controller running QMK. The solenoid is enabled with an SKCL lock switch under the IBM badge. The case is 3D printed, sanded and painted – crahamson.
The author designed the PCB based on measurements of a Model F XT (e.g. the size of the capacitive pads).
I put the XWhatsit controller together, flashed it with QMK supporting the controller and hooked everything up. I was a bit surprised to see it worked almost immediately.
The next step was to design the case. Crahamson wanted it to look like an actual IBM board so he tried to make a 40 % version of a Model F case. He also decided to make the PCB curved like the original which required several iterations of redrawing the case.
The final design (above) has a separate barrelplate that the PCB slides into. This plate in turn slides into the lower part of the case:
If you think adding a solenoid is trivial, check out this implementation: it can be toggled by pressing a stealth button hidden beneath the IBM badge ("I had an SKCL lock switch from an old Apple keyboard that I decided to use").