No, this isn’t a post about how I had a hard life growing up, or anything of that nature. I had a pretty happy childhood as it happens. Most of you will know already, that this is one of Stewart Coffin’s puzzle designs, #41 in his numbering system, consisting of 10 pieces, made from 5 cubes each, which come together to form a 5x5x2 rectangle with a checkerboard pattern.
Unhappy Childhood, boxed in the unique checkerboard solution.
This particular copy was made by me and is made from Rosewood and Maple, with a Myrtle Burl box. It measures 3.7″ x 3.7″ x 1.5″ for the pieces, and 4.25″ x 4.25″ x 1.7″ in the box.
This is a pretty tough puzzle to solve, as there is only one solution where you end up with the checkerboard pattern on both bottom and top as you can see in the picture above. There are however 2,408 possible solutions if you ignore the checkerboard. So no shortage of ways to get a 5x5x2 solution! (Stewart Coffin reports that “a computer analysis by Beeler, these pieces pack into a 5 x 5 x 2 box 19,264 different ways”, however Burr Tools shows just 2,408)
The following is a look at the creation of this puzzle. Hope you enjoy!
This is one of the puzzle designs that I had been looking at making for a while, since it seems no-one has made any in some time, and I don’t have one in my collection. Really that’s where this all started, looking to add a new puzzle to my collection, and having spent (far) too much on puzzle already this year, what better way than to make it myself.
It all starts with cubes
So the puzzles that I’m making currently are all cube based, and that’s where it all starts. 50 wooden cubes, 25 Rosewood, and 25 Maple is the starting point for the UC. The darker tops on some of the Maple cubes at the bottom of the picture is actually the natural wood. Since I love the look of wood, I’m not selectively removing pieces which don’t look perfect. After all each puzzle is unique given the grain and natural colour of the wood, which is something I love. When I put the pieces together, I’ll orient the pieces so that very little of this is visible, because I’m really aiming for the contrast between the two woods in this puzzle. If the couple I’ve made, only one has this distinctive colouring on some of the pieces.
50 Cubes to be Bevelled
One row done, 9 more still to do!
Half way there!
Some time later, and I'm done!
This is one of the most time consuming parts of the process (currently). I have to take all 50 cubes, and put a very small bevel onto each edge of the cube. All in all it takes between 1.5-2 hours with my current method. There’s been a fair old discussion in one of the puzzling forums about beveling cubes, so I’m sure I can cut this down significantly, but that’s going to need a new jig, and some more tools in the shop so for now I’m stuck with what I have.
If you’re interested, the checkerboard piece of wood in the pictures isn’t some sort of template, it’s actually what will become the base of the box that the puzzle sits in. I just happened to be working on it at the same time, hence it ended up in the pictures.
Next up I made the 10 pieces of the puzzle from those 50 cubies, and as it happens I don’t have any pics of the process. I’ll need to take a few from the next one I make and update this at a later point. Anyway with that done, I turned my attention to the box. I now had dimensions for the box, based on the final size of the pieces, so I took the burl I was using to the saw, and cut it to the right lengths for the box, and created a dado in the edges of two sides, to allow me to get a stronger joint for the corners.
The outside edges of the box
Despite the very small contact area, wood glues are remarkably strong, and will hold the frame together with no issues. In fact, to take it apart would probably break the wood, before the glue would let go. Using blue tape, I tape the corners, (no clamping required) and that will hold the box well enough for the glue to set. I do a quick check to make sure that the corners are square, and leave it to dry, while I turn my attention to the base.
The unfinished base, with the sides sitting on top
As you can see, the base is unfinished. The pencil marks were to allow me to line up each of the strips for gluing everything together. As you can see I still have some sanding to do, since there’s glue and all sorts on the base. Thanks to the random oscillating hand sander I got for my birthday, it will make short work of that!
A quick dry fit before gluing the box together.
With the sanding done, I have a quick dry fit with the pieces in place to make sure everything fits as expected before gluing the base in place. Note at this point, Ive sanded the inside of the box to its final point, as it will be pretty touch to get into the corners once it’s all glued together, so best do that before the final glueup.
Box glueup from the top
Box glueup from the bottom
It’s probably worth pointing out at this stage, that I’ve spent around 3-4 hours making this box. Given that I decided I wanted a checkered base, that meant cutting thin, equally sized strips, gluing them together, then cutting them into strips once dry, flipping the strips to create the checkerboard, and re-gluing, then sanding, etc etc. All in all probably the most labor intensive part of the puzzle build, but hopefully worth it!
Finishing. First coat of thinned lacquer applied
With all the individual pieces ready, it’s time to look at finishing the puzzle. The box was all sanded on the outside, and it’s looking pretty good. I start off by applying a coat of thinned lacquer to all the pieces. It’s 1 part lacquer, 2 parts thinner that I’m using. It gives a very thin coat, but does the job or really making the grain pop. If you compare this to the pictures of the dry fir you’ll see what I mean.
First Coat of Watco Satin Wax.
Second Coat of Watco Satin Wax.
Once that’s dry, the puzzle gets two coats of wax. I’m using a liquid wax, Watco Satin Wax to do the job. I leave the wax for around 5-10 minutes, then wipe off any excess with a rag. This is building up a nice finish on the pieces, but there’s still one more step to complete the process. That’s a final buffing with some Renaissance Wax.
The pieces, next to the finished box
A final view from the side, showing the effect of the checkered base. The myrtle burl box almost looks like its floating.
The final puzzle ready to be played with!
So there you have it. I hope you enjoyed the build as much as I enjoyed making it.
