(Truly) Impossible Dovetail box

thingiverse

This clever little puzzle box is my interpretation of the classic impossible dovetail box. It's an intriguing conversation piece, as it's virtually impossible to open unless you know the secret. To build this box, you'll need a small amount of 1/8 inch steel (or another magnetic material) round bar and a strong magnet, along with the 3D printed parts shown here. I found the round bar at Home Depot, but most home goods stores should carry them. For magnets, I recommend using [these](https://smile.amazon.com/gp/product/B06XD2X45M) from Amazon. To print this box successfully, use a 5% infill and a modifier box under the hole that doesn't extend all the way to the bottom if your slicer allows it. If you're not sure how to do this, just use 15% or higher infill for the entire piece – you'll waste a bit more material than necessary, but it will still work. The tolerances on this box are quite tight at .1mm all around (.2mm total tolerance), so if your machine has trouble printing it, try scaling up the model by a small amount. Cut two roughly 25mm lengths from the round bar, making sure 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 secure them in place with magnets from the other side of the box. 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 using the magnets again.