Hi guys, these components are called modular housings, I guess back in the day they were used when membrane switches were replacing mechanical switches and OEMs wanted to use the same keycaps. Various sizes and spacers enabled a way range of custom layouts.
These are the housings, they are molded from ABS.
These are the housings with the plunger in them. Plungers are molded from POM. Keycaps press fit onto the plungers, the bottom of the plungers has a round planer contact surface. The plungers float freely in the housings.
The housings have interlocking features so they can be arranged in a variety of shapes. They’re almost like the Lego of keyboard components and as such the enthusiast community can probably imagine the most interesting applications. They can be surface mounted or you can mill/route/dado a simple channel to accommodate more complex mounting arrangements. Small wood screws or machine screws (#4) bite into the thru holes reasonably well.
I thought this might be of interest if you have a few (thousand) new keycaps you need to organize, store or display or even if someone wanted to do some sort of rubber dome retrofit.
You’ll be able to buy the 3 position housings on the SP website in the new year.