For the joy of making toys

Free plans on how to make wooden puzzles using only basic woodworking tools.

In 1936, Piet Hein was listening to a lecture on quantum mechanics by Werner Heisenberg. It must have been a really boring lecture, because this is when he invented the Soma Cube Puzzle. Like almost everybody I have been known to daydream during class, but I've never come up with anything constructive.

This wooden puzzle is an arrangement of unit cubes to form seven pieces, which must be assembled into a 3x3x3 cube. The pieces can also be used to make a variety of other interesting 3D shapes.

Anyone wondering about how to make wooden puzzles would think it was complicated and difficult. Making this puzzle is straightforward, there is no need for complicated plans or expensive tools.

There is a challenge however, and that is making accurate cuts. The best tool for that is a Mitre Box Saw similar to this one available from eBay.com. |

Cutting Diagram

The first thing to decide is how big you want to make the puzzle. I made this puzzle from a piece of timber 18mm (3/4 inch) square, and there are 27 cubes in the 3x3x3 puzzle.

Which means the timber has to be (27 units x 18mm) = 486mm long plus a bit extra for saw cuts.

There are 14 sawcuts to be made, so that means an extra lentgth of (14 x 2mm) = 28mm.

So, the total length of material is:

(27 x 18mm) + (14 x 2mm) = 486mm + 28mm = 514mm total length.

It's always a good idea to round it off to the nearest standard length, so I used a piece of timber 600mm long.

How would I make this puzzle? Cutting stock into 27 small squares and gluing them back together would be one option. Another way to do it is to count how many squares make up a length in any direction.

The next step to make wooden puzzles is to mark out the pieces to cut. I recommend using a marking knife because you want to be as accurate as possible. The image below shows the pieces cut to length:

- 2 pieces 3 units long
- 8 pieces 2 units long
- 5 pieces 1 unit long

Seven Pieces

Chamfer all the edges with 120 grit sandpaper. The pieces have to be glued to the pattern shown in the picture.

The glue makes it almost impossible to clamp the pieces together without them sliding all over the place. So, what I do is apply a very small amount of glue to each surface and leave it to become touch dry. Then, all it needs is a small drop of glue on one surface and clamp them using only minimal pressure.

Another way is to use rapid set wood glue, which does not require clamping.

I have used Selleys Aquadhere QuickSet, a brand name in Australia.

Methods of clamping

To make wooden puzzles, you can use any number clamping methods, here is a picture of a few that I have used - gaffer tape, elastic bands, weights, spring clamps and g-clamps.

Now that you have made the puzzle, you are going to drive yourself crazy trying to put it together.

Here is at least one solution to the soma cube puzzle or you can watch the YouTube video.

This is a Sketchup model of a large soma cube. Each cube is 600mm square, so that means it would stand 1.8m tall.

A collection Soma Cube figures at a click. Add your own unique figure.

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