Modular 3" rack (for Raspberry Pi and other small electronics)

Have too many Pi's taking up space, or a serious case of rack-envy after browsing /r/homelab? A solution for both!

Included modules (so far):

• Raspberry Pi 1
• Raspberry Pi 2, 3 &4
• Generic tray 109x70mm
• Generic tray 109x70mm (skeletonized/airflow)
• Tray for Fioo Olympus 2 DAC
• Tray for Lexar USB 3.0 SD+CF reader
• Cable guides

Required hardware/BOM:

• 2x 2020 aluminium extrusion - I used generic profiles, but anything with a slot should work I think. I included a test file to check the fit without printing the whole thing.
• 4x M6x16 BHCS - These screw into the top and bottom of the extrusions. If you have Misumi extrusions, you may need M5 bolts instead. 
• 2x M3 T-nut (for each rackmounted device)
• 2x M3x8 SHCS bolt (for each rackmounted device)
• An M5 or M6 tap to make threads in the ends of your 2020 extrusions

If you live in a hot climate, PLA may not be the best material choice. 

Make your own modules:

I've included the (somewhat messy) Fusion360 design file, so you can make changes or use it as a starting point for your own design. Use the template sketch to create your own module and extrude it by -2 or -3mm, then use the rack ears sketch to create the tabs.

Pointers for making your own trays:

Horizontal distance between the two extrusions: 76.2mm

Extrusion size: 20x20mm

Extrusion slot insert width: 5,6mm