Gridfinity is the popular Modular Storage System invented by Zack Freedman. These boxes are compatible with that system but can also be used stand-alone.
The boxes are very functional and work reliably, but the assembly requires specific magnets, and the process is a bit involved.
The complete box consists of two printed parts, the box itself and the lid.
After printing, glue two magnets Ø3x6 into the holes in the box and two magnets Ø3x3 into the lid. (Let me know in the comments if you require holes for different magnet sizes, I can easily create models with different magnet holes. Just keep in mind that space is limited and the magnets in the lid can’t be much longer than 3mm.)
Then, attach the lid to the box using a length of 1.75mm filament. Insert the filament through the holes of the hinge and then “weld” it to the side of the lid (using a soldering iron or a lighter). Depending on your print quality, the holes in the hinges might be too tight for the filament, in this case, try to drill them open somehow.
Printing the lid works best for me with a bit of support over the hinges, otherwise no support is needed.
Print settings that I use:
Update July 26th, 2023:
Upon request from comments, I added a 1x2 box with holes for magnets with Ø2 and Ø6mm.
Update September 1st, 2023:
Added a larger box with size 4x3 elements.
Update September 24th, 2023:
Added a larger box with size 5x3 elements.
Update September 26th, 2023:
Added taller boxes with double the height.
Added a smaller box with size 1x1 elements.
Update November 25th, 2023:
Added a box with size 3x1 elements.
Update June 29th, 2024:
Added a box with size 5x2 elements.
Slightly refined 1x1 box to create more internal space.
The author marked this model as their own original creation.