FREE PROJECT: Making a CNC Domino Set

FREE PROJECT: Making a CNC Domino Set

I was looking over some very old issues of Woodworkers Journal recently. In the May/June 1981 issue, I spotted a very basic plan to make a set of dominoes. While 1981 may seem a long time ago to some of us, dominoes are much older still — developed sometime around 1100 A.D. in China. They migrated to Europe in the 1800s and have been a part of western culture ever since. And as a fellow who has spent some time in cafes in the southern United States, I can report that dominoes remain popular in a variety of games. So with all this history and old-school credibility, why would I look to a CNC router to make the tiles? Well, with 28 tiles per set and a whole lot of holes to drill, it seemed like a perfect fit.

Essential Programming, Bits

First off, if you have a CNC machine you can find the .tap files to make these dominoes in a free download. You will also find a video showing the routing process from start to finish, with a couple of other ideas thrown in for good measure.

I used 1/4″-thick hardwood stock to make the pieces. The CNC program is designed to make use of two 5″-wide by 24″-long blanks, with 14 tiles coming out of each piece. I’ll also add, there are two CNC routing programs to use here. Cleverly named “One” and “Two,” you’ll need to run both to get a properly configured group of 28 dominoes.

Programming CNC Shark to cut a domino pattern
The author used a setup board to help place location blocks on the MDF backer board. This allows consecutive hardwood blanks to be aligned accurately. The blanks need to be identical in size — in this case, 1/4″ x 5″ x 24″. Two blanks are required to create one complete domino set.

Because it takes two boards to make one set, it’s important that you can register each board accurately on your machine. The benefits of being able to take a partially machined blank off the machine and return it for the rest of the cutting process will become even more clear in just a moment. In addition to using a backer board on my CNC Shark‘s deck, I mounted location blocks with screws to position each piece of hardwood exactly. (This, of course, only works if each piece of hardwood has exactly the same dimensions.) With this system, you only set your X and Y coordinates once. I recommend setting your Z-axis for each piece of wood — it only takes a second.

You need two router bits to machine the tiles, the first being a V-bit. Ralph Bagnall, our CNC programmer, recommends a high-speed steel downspiral like the Onsrud bit sold by Rockler. I used a 1/4″ down-shear finishing bit, which I think is pretty similar. It did a fine job. The first process is using the V-bit to score the dividing lines in the center of each tile and also drilling the holes. As I mentioned earlier, there are two sets of tiles — one set per board — and the hole patterns are the difference between the two. The cutout program is the second of the two to run. It leaves small tabs on each tile to keep them from flying around the room as they are cut free of each blank.

Rockler Domino Drilling Template

Using the Rockler Domino Drilling Template and Bit

Not every woodworker has a CNC router, but don’t let that stop you from making a few sets of dominoes if the urge strikes you. Rockler has a drilling template and a specially designed drill bit that makes this a totally manageable task for any home-shop woodworker. And while you could use the technique we practiced in the CNC-made dominoes — painting either the surface of the tiles or painting the dots — another great way to achieve good looking dominoes.

Rockler Domino Templates and Bit

Quarter-inch-thick walnut veneered plywood, when drilled, reveals a lovely white interior wood. How you finish them is up to you, but we would recommend applying a spray finish from a rattle can before you start cutting them out. Then touch up with the same spray once they are cut.

Domino Box based on free plan from Rockler

If you have a table saw, handheld drill and a router table, making dominoes can definitely be on your project horizon.

Planning Ahead

Cutting divider line for domino in maple stained black
Using a V-bit, the divider lines are engraved into the surface of the domino stock. Here, the maple stock is painted black so that the routed lines are easily seen. The paint is non-toxic when cured.

While making these tiles is not exactly the most demanding woodworking a person will ever do, there are still opportunities to be a bit creative and have some fun! Let me explain. Most of the images here show dominoes being made from maple lumber. The maple was painted black to allow the scribed lines and the drilled holes to show through the paint. As you can see, it worked great, creating nice black dominoes with white dots and divider lines.

Using CNC drill bit to cut out domino holes
There are two engraving programs required to make a complete set of 28 dominoes. The dot patterns will be different from each other. A CNC router makes quick work of drilling the many holes.

Taking that two-color idea to the next level, I also used some wenge stock and put a lacquer finish on the wood before machining it. When the lacquer cured, I then put a layer of Frog Tape on top of the board and used the CNC to cut the divider lines and the tile holes. At this point, I took the blank off the machine and painted the dividers and holes white. (Quick tip: it does not work to just spray the masked-off blank with a rattle can of white lacquer to color the dots and lines, or the paint tends to go on too thick.)

Using a downspiral bit to cut out full dominos in maple wood
Cutting out the tiles requires a 1/4″ bit of some sort. Our CNC expert recommends a high-speed steel downspiral bit for this effort. We tried a carbide downspiral bit and had satisfactory results.

So with the Frog Tape still in place, use a stiff paint brush to paint the holes and lines by hand. It does not take long at all. Once it dries, remove the tape and step back to the CNC machine. Using the location blocks, slide the blank in place, secure it to the backer board and cut out the dominoes. The wenge version looked so good that I repeated the process using padauk wood and painting the dots and dividers black. They looked great too.

Small wood connective pieces between cut dominoes
Wood tearout at this point would be very frustrating, so use a proper bit. The cutout program leaves tabs that connect the tiles to the blank to prevent loose dominoes from catching on the bit and flying across the shop.

When the tiles are cut out, the CNC leaves small tabs connecting the tiles to the larger blank. Carefully break the tiles free and then sand the tabs flush to the edges of the tile. I used a benchtop belt sander and actually sanded all four edges of each tile smooth.

How to Finish

Using a benchtop belt sander to finish smoothing out the domino edges
The author sanded all four edges of each tile to remove the tabs and machining marks. To speed that process up, he used a benchtop belt sander. He also left the edges of the tiles unfinished.

One quick safety note: while dominoes are not a little kid game, they could get their hands on them. When they do, you can bet they will put them in their mouths. (We made these tiles large enough to not be a choking hazard, but still, keep them away from little kids.) Be sure to use paints and finishes that are non-toxic when they are cured — which is almost all of them. It is always better to be safe than sorry.

Speaking of finish, I left the edges of my dominoes unfinished. I liked the contrast between the surfaces, and there is no reason to finish the edges to control wood movement. (Plus, it would have been a pretty fussy process.)

If you’d prefer to finish all the surfaces, a good way to do that is to wait for the main finish to cure completely and then wipe a coat of paste wax onto each tile. In a minute or two, wipe the wax off and you will have finished the edges with a minimum of fuss.

A final idea that I have not yet tested would be to apply a really fancy veneer to both sides of a contrasting core. You would need to apply veneer to both sides to keep the pieces from distorting. Veneer options are pretty inspiring. Imagine bringing out your Carpathian elm burl dominoes — very fancy!

Whether you make these dominoes using a CNC or a drilling jig , the result will be a custom-made game that will provide years of pleasure.

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