This is a case I designed for the Adafruit PyPortal. I needed a case I could keep on my bench and not worry about destroying the PyPoral due to the mess on said bench. It was designed in Fusion360 and is 3mm thick. The cover fits right on to the back of the case.
Four M3 x 6mm screws were used to mount the PyPortal into the case. The screw offset on the right (as looking from behind) is tight against the PyPortal, just a tiny bit of sanding will allow the PyPortal to fit in smoothly. I didn't want to make the offset any thinner there than it currently is.
The NASA picture of the day code provided by Adafruit is currently being displayed in the picture used for this Thing. Maybe if I get my own code working right I'll change out the picture to show that off.
Blog post to go with this Thing https://3darduinogeek.com/2021/01/01/my-pyportal-case-design/