Cherry MX to Datanetics DC-51 Keyboard Switch Adapter

These parts let you replace defective (and soon-to-be-defective) Datanetics DC-51 switches used on some Apple II+ keyboards with commonly available Cherry MX ones.

Printing Notes

Disable support generation for the keycap adapters.
Enable support generation for the switch adapters.

The stems on both sides need a snug fit, be careful if you have to remove a keycap from the adapter - breaking and subsequently fishing out a stem is not fun. (For what it's worth, I had this happen multiple times with earlier iterations of my model in PLA, only once with PETG.)

The infill setting hardly matters as there are so few spaces where it can be used at all.

Print spares.

Post-Printing

Check your dimensions

• an undersized DC stem or an oversized MX hole means the cap could fly off on a sudden release of the key;
• an oversized DC stem could crack your keycaps;
• oversized pins on the switch adapter will hinder seating on the PCB.

Assembly

1. Solder two (approx.) 2 cm lengths of small gauge wire to the MX switch. (I used 26 gauge enameled wire but other types of solid wire should also work.)
2. Insert the wires in the guide-holes.
3. Clip the switch into the adapter.
4. Cut and strip the PCB-side wires.
5. Reuse the screws fixing the DC-51 switches to the PCB for the switch adapters.
6. Solder the wires to the keyboard PCB.
7. Put the keycaps on their adapters.
8. Mount the keycap adapters onto the MX switches.

Additional notes

Spacebar Stabilizer Wire

You'll need to partially unscrew the spacebar stabilizer retainer clips to install or remove the stabilizer wire with the switch adapters installed, due to their larger footprint at that height versus the DC-51 switches.

Specification Deviation

Note: The MX stem hole in the keycap adapter is slightly oversized: 1.25 mm thick cross whereas official Cherry spec says 1.17±0.02 mm. (Source: https://www.cherrymx.de/en/dev.html)

CAD Links

Switch base: https://www.tinkercad.com/things/12udcAePK2T?sharecode=B7vT58ra5Wn6TgHJFJEuySpw54i0qUaYmlDvqpZHiow

Keycap adapter: https://www.tinkercad.com/things/lMbRnojhf6x?sharecode=COgzbTb4wd9uu2e7dFD94oSeaHVAVPKaNBmTjfTRfY8

(I might revisit this using a more capable parametric CAD program, but won't commit on the how and when yet.)

Thanks and Attribution

Used this Cherry MX switch model by user "gcb" : https://www.thingiverse.com/thing:421524

Though it is not used in my final models, this Datanetics DC-51 keystem model by user "option8" helped a great deal with early iterations of my design : https://www.thingiverse.com/thing:480528

Thanks to the Applefritter forums for their feedback: https://www.applefritter.com/content/cherry-mx-datanetics-dc-51-keyboard-switch-adapter