Magnetic Locking Box

Magnetic lock box, uses magnets for the hinge and for a keyed lock. There are two versions, the locking box requires a ferromagnetic filament to work (like [ProtoPasta's Magnetic Iron Filament*](http://amzn.to/2gA3lHR)), the non-locking box works with regular filaments. I don't actually have a use for this, but I've been wondering for years if this would work.

Hinge - The hinge uses 4mm cylinder magnets as the center of the hinge. By reversing the direction of each magnet (north to north, south to south), you can form a spring that works as the axis of the hinge. You can see the [4mm x 10mm cylinder magnets*](http://www.banggood.com/50pcs-N35-Super-Strong-Disc-Magnets-4mm-x-10mm-Rare-Earth-Neodymium-Magnets-p-1000661.html?p=EY011634303112016018) inside the hinge in one of the pictures above (shorter magnets will work too, but more of them will be needed). In the magnetic iron box, the hinge can be made with only two magnets since they will attach to the side of the box, but it