Tangram Puzzle and Gift Box

My daughter loves puzzles. Her birthday was coming up and my wife found a Tangram book in a thrift store. I was then tasked with making a Tangram set to go with it.

Tangrams are puzzles. You are given an image, and a set of seven shaped tiles that you need to figure out how to arrange to make into the provided image.

Along with the seven tiles, which are pretty straightforward to create, I set about making a storage box which was large enough to hold the tiles as well as the book. (And also large enough to be useful in other ways, should my daughter ever decide that Tangrams no longer hold any interest.)

I started with the book. That guided the dimensions that I would need to work towards.

Along with that, I googled up a Tangram tile pattern online, which I scaled up to a size that I liked and printed out on some paper.

I then went to my "too good to throw out" pile of small lumber and found some 3/8" thick cherry pieces left over from a previous project.

The Tangram tile patterns where cut out and glued to the paper with some spray adhesive. These were then cut out on the bandsaw and sanded to final shape.

So far, this is looking like a 15 minute project. The tricky part is next.

I went back to my lumber stash and pulled out these boards.

On the left are few quarter-sawn white oak boards which my brother gave me. On the right is a piece of (roughly) 3/8" thick spalted maple which I've been hanging onto for years. Spalted maple is just too gorgeous to throw out or burn, so I inevitably hang onto any small scrap of it, just waiting for the right project.

My plan is to use the white oak for the body of the box, and the maple for the top and bottom. For dimensions I just placed the Tangram puzzle book down and measured so it would be a bit larger than that in both length and width, and around 3" tall.

I trimmed the pieces to size and used my Woodgears Box Joint Jig to make finger joints in the ends.

(I purposely skipped over details of that, as I doubt that everyone has this finger joint jig. There are multiple finger joint jigs out there, and any one of them would work. And of course there are also many other ways to make a small box, be it with butt joints, dowels, miter joints, and so on.)

I also ploughed dados along the top and bottom inside edges to receive the top and the bottom pieces. My plan was to have a sliding top, so one end was also cut short, so that the lid could slide in over top of it. The bottom was fit into place (without glue, like a floating panel) and the finger joints were glued together.

The dado cuts had left a few tiny gaps at the ends which I plugged with some small pieces of oak. These will be practically invisible after sanding and finishing. Right now you can just see a few of the "patches" in in the first photo, in the lower section of the joint, standing proud of the other pieces.

The second photo shows the bottom of the (finished) box, showing how the piece is captured in the sides, in that dado.

Now, I'm sure that some people are curious about my box joint process. so here is a video where I go into detail as to how to use my Finger Joint Jig. (aka Box Joint Jig)

This video is NOT about this Tangram gift project, but I'm including it here for those people who are curious about the jig.

( I also have a website article about building this jig, but if you really want to learn about it, you should go investigate the website and youtube channel of Matthias Wandel, who is the one who invented it: woodgears.ca/box_joint/ )

I used a stationary belt sander to sand the fingers flush, and to round over the corners.

A piece of the spalted maple was cut to fit as the lid. It was a touch thicker than the dados, so three of the edges were sanded thinner back on the belt sander. This gives the entire lid a sort of raised-panel appearance.

As well, a small piece of oak was attached across the end, partly as a finger pull and partly as a fill-in trim piece. It is a cross-grain joint, so there are just a few dabs of glue in the joint. The main source of strength, though, are provided by two small screws fastened in from below, to allow for wood movement.

Here is the box and Tangram pieces, sanded and ready for finish.

I applied several coats of spray lacquer (from an aerosol can) to all sides of the project. For a small project like this, "rattle-can" spray-lacquer is a quick and easy finish. Lacquer dries incredibly fast, so you can apply several coats in a short stretch of time. Bear in mind, though, that you do need to leave the pieces afterwards to off-gas and cure.

I was thinking that the pictures make this seem like a tiny little project, but don't be fooled.

The Tangram tile set is almost 5-1/2" square.

The book is 4-3/8" x 7-1/8" in size, so it requires a good sized box. The final dimensions of the box are about 5-3/4" x 9-1/4" x 3" thick. (With 2" of depth on the inside.)

Here are a series of photos of the finished piece.