This is a modular desk / wall organizer I made. Each piece slides together with a very firm tolerance. Depending on your print settings this can be made looser or tighter, the top clips I left a bit loose.

It's designed to be expandable, currently I have trays that are multiples of 2.4" by 4", this gives a 3x5 grid that forms a 1 foot square area. These print very strong, and the largest of the boxes only takes about 2.5 hours, the 1x1 box takes about 2 hours.

There are mounting points on all sides, and these can be remixed easily to make wall mounts or adapters for the edges for things such as tool holders, pencil holders, or other utility components. (I will add them as I make them)

If the holes on the bottom are an issue, I'll add a cover if requested that's just a flat piece to cap off the bottom. Let me know in the comments.

Read the print settings carefully, I printed these without supports :)

-Initial Layer Height (layer 0) = 0.18
-Line width = 0.4
-Supports will add time, and are unecessary if you make a small edit to the g-code file, see note at the end.
-2 walls
-z seam (in cura choose back right corner, hidden seam)
-fill small gaps nowhere

If you use Cura, you can find the layer that the overhangs start at in the g-code easily, with these settings for me that was layer 109 and 110, it looks something like this:

;TIME_ELAPSED:7094.491878
;LAYER:109
;TYPE:
;MESH:Desk Wall Trays 1x2 v2.stl
G1 F2640 X161.312 Y49.146 E1334.43217
G1 .. bunch of G1s, and a G0, then another section, several sections, then the next layer

After each section between the "LAYER:XXX" comments for 109 and 110 for me, I changed the feed from 2640 to just 640, and it printed those two layers slow enough for the 90deg overhang to print perfectly, no sag or distortion without the need for supports. This cut off about 20 minutes print time or so for me. The layers will probably not be the same for you unless you use the exact print settings I have but even then, just use the layer preview and find the first layer that has a bridge over the "windows in the walls."

Ultimaker

Ultimaker 2

No

No

0.24MM height, 0.4MM Nozzle

25-35%