Finally got my Uno off the zip ties and onto a proper DIN rail mount

Did the same thing for my pool timer project last summer and it's still holding up. Mine lives next to the pool pump controller where it gets pretty toasty in the afternoon sun, so I also skipped PLA and went with ABS, mostly because that's what I had leftover from another job. The clips are the part I'd think about though. Mine cracked eventually and I realised I'd printed it standing up, so the layers ran right across the thin part of the clip and it just peeled apart one day. Reprinted it flat on its back and the second one has been fine for over a year now. One other thing I found handy was leaving a bit of slack in the wiring loom inside the cabinet. Even with the board firmly clipped, if the wires are pulled tight they'll drag on the rail every time you open the door, and mine slowly worked itself along the rail by a few millimetres til I gave it some slack.

I ended up adding a zip tie through one of the rail slots as a belt and braces measure after the first clip cracked. Cheap insurance for something that sits above a bunch of relay wiring. Your bolt idea is nicer than mine, mine just hangs on friction and the clip alone.

I took a lazier path with mine. The Uno lives in the shed running the chook door and a fan timer, and instead of printing a bracket I cut a short length of spare rail, screwed that to the back wall of the enclosure, and clicked one of those cheap snap-on carriers underneath it. The board sits on nylon standoffs bolted through the corner holes, and the whole carrier lifts off the rail in one move when I need it on the bench. Ten minutes with a hacksaw and a drill versus an evening in FreeCAD, and I'm not a patient man.

The other thing that helped was stopping the constant plug fiddling that made my board swing around too. I feed it 5V from an old phone charger now, so the USB lead only goes in a couple of times a year when I actually change the sketch. Between that and the carrier it hasn't moved in about eighteen months, even with me banging around in there stacking feed bags.

I noticed that when you mount these large single-board computers, the structural integrity of the mounting points can be compromised by thermal expansion. Specifically, the internal components will shift slightly when the enclosure warms up, which coud induce some unexpected torque on those M2 fasteners. I recommed ensuring the nylon washers are properly seated, as I previously found that adding those under the head significantly minimized high frequency vibration even in a seemingly rigid setup.