Kada Spectrum - a 65% mechanical keyboard

This is a 65% mechanical keyboard design inspired by the ZX Spectrum computer using the KBDfans Tofu65 2.0 PCB. It's originally designed to be printed on a Voron 2.4r2 300 but any printer with enough space should be able to do it. The included 3MF file show the suggested orientation but you'll have to figure out how to best fit things on a plate. Refer to the CAD model (STEP) for how to fit everything together.

Both the top part of the case and the bottom cover are assembled using press fit dowels without any glue, although you can use glue if you like. The dowels are designed without any clearance except for their length. This may or may not work well depending on the tuning of your printer or your chosen filament but if you feel like it's too tight, sand them down so they fit more easily but are still snug. I used the rubber handle of a large screwdriver to hammer them in, carefully.

The accent pieces are designed to be printed as single pieces with filament swaps but it's also possible to print them single color or to split them up in CAD/slicer.

The plate is split into three parts which makes it somewhat tricky to put the switches in but feel very nice once fully assembled. I suggest you put together the entire plate assembly before putting it in the case.

I originally printed this in Addnorth X-PLA for the main parts, Addnorth E-PLA for the rainbow accents and Addnorth HT-PLA Pro Matte for the plate. I'm sure any generic PLA will work and you can experiment with PETG, ABS and other things if you want.

While it's currently designed for the Tofu65 2.0 PCB, it shouldn't be rocket science to modify the CAD model for using another PCB, especially if it also uses a daughterboard.

Supports are likely needed in some places, use your own judgement. I used traditional supports for counterbore holes and similar. For the top case parts printed at 45 degrees, I used organic supports, automatic.

BOM

• KBDfans Tofu 65 2.0 PCB
  • https://kbdfans.cn/collections/tofu65-2-0/products/tofu65-2-0-accessories?variant=41179820294283
• KBDfans Tofu 65 foam kit (optional)
  • https://kbdfans.cn/collections/tofu65-2-0/products/tofu65-2-0-accessories?variant=41179820327051
• 12x 80x4x3mm Poron foam gaskets
  • For example: https://kprepublic.com/products/kprepublic-gasket-strip-gasket-pad-pads-stickers-foam-poron-material-for-mechanical-keyboard-le20-black-thick-round-corner?variant=43459474227363
• 4x 12.6 x 3.5mm round rubber feet
  • Holes for feet are 13x1mm so anything 12-13 mm in diameter should work
• 12x M3x6 flat head countersunk screws (for attaching the bottom cover)
• 8x M3x8 socket head screws (for attaching the retainers that hold plate in place)
• 4x M2x4 socket head screws (for attaching the daughterboard PCB)
• 20x M3x5x4 heat set inserts (the Voron kind)
  • The CNC kitchen ones are great
• 4x M2x3 heat set inserts for daughterboard PCB
  • Again, the CNC kitchen ones are what I use
• Keycaps, switches, stabs, all the usual things

Thanks to the original creators for creating the CAD models used in the STEP file:

• Switches: https://grabcad.com/library/kailh-polia-switch-cherry-mx-compatible-1
• Heatset inserts: https://www.printables.com/model/482734-threaded-inserts-heat-set-inserts-by-cnc-kitchen
• Keycaps: https://github.com/hineybush/CherryMX