Raspberry Pi 4/5 1U rack-mount bracket

A bracket to mount the Raspberry Pi 4 or 5 in a standard 19-inch server rack. This will fit 6 RPi 4/5 units using Power Over Ethernet (PoE) in a 1U space for a very simple and tidy cluster solution. I use the official PoE hat with the RPi 4 put out by the Raspberry Pi Foundation that normally sells for $20. I am still waiting for the official PoE hat for the RPi 5 to test it but the board itself is a good fit.

This is a variation of a 2U bracket that I worked on earlier:

* [Raspberry Pi 4/5 2U rack-mount bracket](https://www.thingiverse.com/thing:4078710)

and uses the same tray design, so you can move units between these two mounts easily. This design fits 6 units in 1U, and the other fits 12 (or 13) in a 2U space. This 1U design lets you build incrementally, but personally I prefer the 2U design and recommend it over 2 of the 1U racks if you will need more than 6 units total.

Here are all of the parts you will need for a complete 6-Pi cluster:

To print:

* 6 frame parts
* 6 tray parts
* A pair of ear parts (both ears are in a single file)

Other hardware:

* 2 threaded rods cut to 17 5/8 inches. I recommend buying a 36-inch rod, which is enough for two finished parts. Cut it with a hacksaw or a Dremel tool with a cutoff wheel. I suggest #10 size in the USA. Not sure which metric sizes are commonly available, but M5 would be a close match (you will need to download the OpenSCAD files and adjust the hole sizes).
* 4 hex nuts that fit the threaded…