handwired 40% from a bag of spare switches

After swapping switches on my main board I had 48 left over. A 40% needs 47 or 48 depending on layout, so that more or less decided it.

Plate is printed in PETG, two halves with a dovetail in the middle because my printer bed is too small for the whole thing. First version had 14.0 mm cutouts and the switches needed way too much force. 14.1 mm is fine.

wiring

Diode per switch for the rows, bare copper wire for the columns, heat shrink where they cross. Took two evenings and most of that was stripping wire. Controller is a cheap pro micro clone running QMK.

Spent an hour debugging one column that was soldered one position off. Label your columns.

Next time: more walls on the plate (it flexes a bit in the middle), and plan the wire routing before soldering. Three layers ended up being enough. I use it every day now.