Here is a simple wooden puzzle box. My box is made from old mahogany floor-planks. You can make this box from almost any kind of wood. I used 45 degree joints, but you can make different ones if you want, or do not have a bandsaw/tablesaw.

The key is
just a 0,5mm piano wire. Almost any kind of metal rod will work. The mechanism is very basic.

Tools/materials

wood

sacrificial drill bit/metal rod.

Woodglue

Bandsaw/tablesaw

Sandpaper

dremel

Step 1: Cut Out Squares

Saw your wood into 6 squares.

Step 2:

Make the center pin. This is the birch wood piece see pictures. I made this piece by laminating two fire starter planks together. (1.picture).

Now make two countersinks to fit the center pin. The countersinks are made in two separate blocks. Do not drill all the way trough. To make the countersinks a dremel is useful.

To insert the metal rod witch functions as the locking pin you need to drill a hole through the “bottom” piece. A long drill bit Is recommended. The diameter of my bit was 4mm, but anything from 1-8mm will work. Try making the hole as straight as you can. Notice I did not make the hole centered I added a slight offset. This is to make space for the hole in the center piece. Drill the hole with the center piece inside the countersink .

You will also need a small metal piece the same diameter as the hole you drilled. If you do not have a metal rod the same diameter you can just cut of a piece of your drill.

Step 3: Cut 45 Degrees :

In this step I recommend using a bandsaw, or a table saw. Not the type of saw I used here. But If you do try making a hold down jig to prevent your fingers from touching the blade.

Step 4: Cut the Center Pin to the Right Length:

apply oil to the metal rod you just cut out, to make it slide better.

Cut the center pin to the right length.

Step 5: Gluing:

Lock the center pin by pushing the metal rod until it is closed. Apply glue to all the sides of the pieces, except the sides witch mates with the top piece. (and the top piece). When it comes to the top piece fill the countersink with glue. Tape everything together as tight as you can. It is important that all the sides align correctly. Place the top piece so that the glue does not slide down and mess up the mechanism. Place the top piece down on the table.

Step 6: Drilling Final Holes:

Sand the box down and add some sort of oil or lacquer if you want.

Mark on the outside of the box where you made the hole for the metal rod. Drill a holes where you marked. You do not have to dill, you can also use a needle or something small to make the hole.

You also need a key.

I forgot to take pictures. But all you really need is a stiff metal rod. The one I use was a 0.5mm piano wire.

This is a very basic design. And I did not put much effort into hiding the holes. The original plan was to use a magnet to push the metal rod, but I did not have strong enough magnets so I ended up with making a hole, and a push “stick”.
I hope this intractable makes sense.