The keyboard is a copy of the original AIM-65 Keyboard but using Cherry MX key switches.
The spacebar can be supported by either two additional MX switches or a keyboard stabilizer, I bought a pack of ASHATA gold screw-in stabilizers from Amazon (I only used the spacebar stabilizer so have the shorter ones left over and will include one with each PCB purchased, you just need to fabricate a longer metal U piece to fit the spacebar). The holes for the stabilizer screws are not quite correct and need some slight fettling with a needle-file !
I bought plain white keycaps from 'keyboard fun store' on Aliexpress - 1u R3x4, 1.5u R3x50 and 6.25u R1 Spacebar. I plan to add some labels at some point.
Schematic
Bill Of Materials
Blank PCB