Decided to hand-wire my own macro-pad and ended up creating a parametric design in Fusion 360.

You can change the number of keys on the X- and Y-axes using the parameter function in Fusion 360. You can find the Parameters under the ‘modify’ tab. A 4x5 layout is used in the stl file.

The case and plate screw together using M3x16 bolts, no standoffs necessary. There is no reason to use all the available holes to mount the plate, it was just necessary for the parameters to work properly. The height between the bottom of the case and the plate is 10mm as default. You can increase it using the ‘KHE’ parameter but I haven't properly tested whether or not adjusting the height breaks the model.

The plate only fits MX style switches, I built mine using Gateron Low Profile Reds and Browns, I also tried Logitech switches, Outemu switches and Cherry switches with success. The micro-controller used is an Arduino Pro Micro (ATmega32u4). The generated plate is the same size you get when creating a keyboard layout from keyboard layout editor, meaning you can create you own plate design on the website and use the case in this file. The plate in this file only fits 1U switches so if you want bigger keys you will have to create your own plate design.

I also uploaded a simple, low-profile keycap you can print 

Use 0.12mm layer height, There is a 1 layer support withing the model to properly support the holes for the bolts. If you use a different layer height this support will not be generated and you will need to use your own support which will be harder to remove. The built-in support doesn't need to be removed, it simply breaks off as soon as you screw the bolts into the case.

A crude way of creating an angled case is by printing two 9.5mm cylinders at your preferred height and gluing them to the bottom of the case using superglue by using two holes originally created for the rubber feet.

Parts needed to create a complete custom macro-pad:

• Arduino Pro Micro
• 1N4148 diodes
• MX style switches and keycaps
• Copper wire (I used 18 AWG solid core bare copper and 24 AWG insulated wire)
• M3 bolts
• Heatshrink tubing and electrical tape

This case design has been inspired by the 3x3 macro-pad ‘Scotto9’ by Joe Scotto. The case design was made from scratch in Fusion 360 using Joe's case as inspiration. ‘My’ case has smaller walls, holes for bolts and holes for 10mm rubber feet. This model is published using the same license. Joe has a great tutorial on how to hand-wire your own custom macro pad on his YouTube channel ‘Joe Scotto’, in the video bellow he explains in great detail how to build your own and which tools you need.

Joe Scotto's GitHub: https://github.com/joe-scotto/scottokeebs?tab=License-1-ov-file#readme

Joe Scotto's website: https://scottokeebs.com/

Joe Scotto's tutorial: