Simple Universal Cereal Dry Box Spool Holder (No Drilling Required)

The original design is simply the best solution for filament storage and printing I have found so far, being small, cheap, smooth, easy to make, and easy to use, all without any modification to the cereal box.

But I thought I could improve it a bit by adding a hygrometer mount to monitor the humidity levels, a small filament clip accessible directly from the opening, and hexagons to even further reduce the amount of filament needed to print it.

These small changes work great, I don't have to fiddle with the spool at all from loading to unloading, and everything is sealed by gaskets during use or storage.  Moreover, the whole thing sits snugly, allowing to print with the box upright or on its narrow side, and to store it in any orientation.

Note: you will need to get the lid from the original design page, as I only uploaded the parts I modified

Also, assembling the roller might be hard depending on your printer's tolerances, but nothing a good hammer didn't fix on my side :P

Finally, I recommend printing it in PETG for its strength and bending compliance, especially the roller, as PLA might be too stiff/brittle

Changelog:

17/03/2026: Extended the roller to fit Esun spool a bit better; Shortened the frame so that it would sit further from the bottom of the box (old version is now called "Longer")

10/12/2025: Added another lip on the upper part for easier printing + chamfered the roller so that it's easier to mount a spool on it

28/11/2025: Added a lip on the lower part for more stiffness