This .scad will generate Cherry MX key switch testers of any length/width. The cutouts for the switches will be automatically centered.

Also included is cherryVoid.scad which includes a negative (void) space cutout of the precise shape you'll want when creating keyboard mounting plates, custom key switch testers (e.g. with text), and basically anything else you'd want a Cherry MX key switch hole.

Pre-generated key switch testers of varying sizes are also included.

UPDATE 20200302: The interior of the switch tester now uses rounded corners (no more sharp edges) and I've added an option to include a keyring/cord hole in the corner (makes a great keychain/fidget toy). All examples have been re-rendered and the 1x1 model includes the keyring hole.