Puzzle Box

Finished in December, 2006


After returning from Japan with some lovely wooden puzzle boxes, I decided to make one of my own. The original idea for this box was to make a square box whose "trick" was that one must twist the top to open it. This was made non-obvious due to the square shape of the box, and also because of a small detent pin in the cylindrical brass interior - this pin would allow the top to wiggle slightly, but there would be some clear resistance to twisting it. It occurred to me belatedly that this is actually a very poor trait for a puzzle box. I'm of the opinion that the trick to opening a box shouldn't ever be "just push/slide/twist harder", because that trains puzzle box fans to break the delicate ones. Never the less, that was my plan, and I was excited enough with the idea that I built it anyways.


The design changed somewhat during construction, and the result is that the box is not particularly difficult to open. Katherine really liked the way the top set into place, and thought it was a shame to cut the box in half as I'd planned, so I revised the design: instead, one would press up on the bottom, and the top would pop up out of the sides. Then, one could twist it and open the box. However, the need to press up on the bottom is pretty obvious, and the dovetail notches make it possible to see enough of the brass mechanism that the twisting is pretty obvious too. This design is more fun to operate, but the previous one would at least have hidden the brass mechanism properly. Katherine says I only think it's obvious because I built it - we'll see, I suppose. In any case, I'm pretty pleased with the result over all. It's a very nice little box.

The box is made of the same lovely cocobolo I used for the ends of my concertina, and the dice box. The walls are shaped vaguely like puzzle pieces that interlock as they go around the box. They each have a dovetail on the right side, and a notch for a dovetail on the left. Then, the top has a dovetail on all four sides and is set into the walls. I'd never cut a dovetail joint before, so this was good practice. It's not as bad as I'd expected, but then some of my joints are pretty sloppy too. The ones in the walls look pretty good because I used an old trick: Glue them with epoxy, and sand off the excess. The epoxy cures somewhat dark, and fills all the gaps. It's really amazing how it can make your joints look a little tighter, at least to a casual eye. You can look at the joints around the top for a better idea of what the side joints would look like without the epoxy. Unfortunately, this contrast makes it pretty obvious that the top must move upwards.

[Cylinder] [InsideTop]

Here you can see the brass internals that form the "twisting" part of the box. The top has a couple of pins that slide through a groove in the cylindrical base. There's also a spring-loaded detent pin that sits in a hole in the base when the box is closed. There's just enough freedom in the hole that the top can wiggle slightly, and that resistance is felt if you try to turn it. The trick, again, is simply to turn harder. Then the pin pops into the top, and the top can be twisted and pulled off the base. The brass cylinder is secured to the wooden base by four small machine screws. The heads of the screws are actually concealed beneath the wooden feet of the base, but since the feet are glued in place the screws are unlikely to ever be removed.

[Bottom] [Branding]

In order to sign it, I tried something new: a brand. I really wanted to finish up, so it's a fairly simple symbol intended to resemble my initials. I made this small brand out of plain steel wire, and it works surprisingly well. The handle is short (4" or so), but even so you can heat it up red hot without your fingers getting warm (steel's nice that way). When red hot, it burns the wood "like butter", and gives reasonably consistent results.

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