I am a longtime fan of puzzle boxes and wanted to make one that uses a magnet to open. This box was inspired by Walter Hsiao's magnetic box. I loved his concept of using opposing polarity magnets as hinges.
Installing HInges: Each hinge uses 2 opposing 1/8in x 1/4in magnets. The reversed polarity creates a 'spring' feel that keeps the magnet extended into the void on the base.
The latch mechanism is comprised of a 1/8in x 1/4in magnet stacked on a 3/16in x 1/32in magnet. This portion goes into the large opening on the latch (back side). Another 1/8in x 1/4in is pressed into the small cover so that when installed it opposes the stacked magnets.
In the top corner of the lid, and top corner of the base, there is a spot for a 1/8in x 1/4in magnet. These are installed opposing and force the lid to pop open when the latch is depressed.
Lastly, a 3/8in x 1/8in magnet is pressed into the 'key' piece. when installed correctly, this should oppose the latch from the outside.
If anyone has any issues installing magnets, I can make a video showing assembly.
I made the first print with MeltInk PLA @230/60. I also used a brim to keep the corners of the lid from warping or coming off the bed.
Where to buy Magnets
Here is a list of the parts needed for the hinge and locking mechanism (Click on Name to go to source):
6x 1/8in x 1/4in N52 Neodymium Magnets
2x 1/8in x 1/8in N52 Neodymium Magnets
2x 3/16in x 1/32in N52 Neodymium Magnets
You will also need a magnet for locking/unlocking the box. There is an included STL file for a key that fits a 3/8in x 1/8in N52 Neodymium Magnet
NOTE: The only magnets that are NOT installed reversed polarity are the 3/16in x 1/32in coupled to the 1/8in x 1/4in that is used for the locking mechanism. All the other magnets need to be installed so that they repel the magnet they are next to - like a spring.
TIP: Large Channel locks (pliers) work great for pressing the magnet into the cap, and pressing the cap into the back of the locking mechanism. Make sure to use something like a thin piece of wood or plastic between the pliers and the lid so you don't scratch or mar it.
TIP: The tolerances on the box didn't leave much wiggle room. When assembling the box, you may need to sand off any edges or bumps that aren't supposed to be there. Additionally, I drill out all holes on the lid, and hand turn a drill bit in the bottom to clear out any debris. In order for the box to assemble and work properly, the magnets need to be able to smoothly move in/out of all voids.