(Truly) Impossible Dovetail box

thingiverse

This little box is my take on the classic impossible dovetail box. It's an interesting conversation piece, because unless you know the secret it is literally impossible to open. You will need a bit of 1/8th inch steel (or some other magnetic material) round bar and a fairly strong magnet as well as the 3d printed pieces here. I got the round bar from Home Depot, but I imagine that most home goods stores would have them. I used [these](https://smile.amazon.com/gp/product/B06XD2X45M) magnets from amazon. I suggest using a 5% infill and a modifier box under the hole that doesn't go all the way to the bottom if your slicer allows it. I set the infill for the modifier to be 15% and rectilinear with good results. If your slicer doesn't support it (or you don't know how) you can just use 15% or higher infill for the whole piece, you'll just waste a bit more material than is strictly necessary. The tolerances are fairly tight at .1mm all the way around (.2mm total tolerance), so if your machine has trouble you might want to scale up the model by a bit. Cut two roughly 25mm lengths from the round bar, making sure that the ends are smooth. The exact length doesn't matter, as long as 22<x<28. Insert each bar into the deeper hole of the two box halves, and from the other side of the box secure them in place with magnets. Now you can assemble the box and remove the magnets. The rods will fall into place, and you won't be able to take them back apart with using the magnets again.