Easily mount your pi in your rack with magnets OR you can have a really expensive fridge magnet. I use the POE Hat + in these to cut down on wires.
I started this for a different project but the tray became the most useful part by far. It's a simple slab of PLA that holds two magnets (60mm x 10mm x 2mm magnets - search that on Amazon) and four m2.5 hex nuts.
Basically the print needs to pause twice, once for magnets and again for m2.5 nuts.
I was going to print an entire rack mount for my 4 raspberry pis but with these I'm able to mount them on the 1U shelf and on the bottom of my other rack mounts. Works great - would love to see some tweaks. The hex nut is definitely the weakest point of this design. I believe I used between 12mm-16mm m2.5 screws.
TPU on the bottom layer would be a good tweak as well - the PLA tends to slide but a TPU layer could be great.
The author marked this model as their own original creation.