If you are interested in the vector files for this project either click here or scroll to the bottom of this post (above the comment section).
Every now and then I get the opportunity to share the joys of woodworking with someone else. In this case, my wife’s nephew, Kagan, came to spend the weekend with us. He’s 16 years old and a black belt in kung fu. Being a black belt is a great achievement but it also lets me know that he is accepting of instruction. Coming into the weekend he had the goal of making a clock for his Sifu (kung fu master).
I explained that it would be best to make two clocks. This would allow me to demonstrate what to do on one clock first and allow him to complete the task on the second clock. One clock would be given to Sifu and he would keep the second clock.
Our initial plan was to use Bubinga for the outer ring of the clock. It would have looked great with the darker red color of Bubinga but unfortunately, I did not have enough on hand. Instead, we chose mahogany. Step one was resawing the 8/4 mahogany into two 4/4 boards. Here he learned how to properly use the bandsaw.
At this point, all of the wood we picked out can be jointed and planed. Making sure to get 3 sides flat and square. Here he learned how to properly use the jointer and planer.
Kagan wanted a yin yang clock which means we need two high contrast colors for the center. We chose ash and wenge for the center and the mahogany will make up the outer ring with the clock numbers.
Now all the pieces can be glued up to form panels. We let the panels sit in clamps overnight. Here he learned how a carpenters triangle can be helpful in panel alignment and how to clamp from both sides to prevent a bow in the panel.
The next morning we scraped any glue squeeze out and skip planed all the panels to clean them up.
First up on the CNC was the ash pieces. You can see the highest point of the cut extends further than the actual piece does. This is because we tried to first cut it so that the small end terminated at a point. The sharp point just broke off. There wasn’t enough supporting material. So with it still mounted to the CNC machine, I changed the short side to terminate with a radius rather than a point. This cut cleanly without any tearout. We also added a shallow pocket and a plug. Here he learned how to locate and secure material onto the CNC machine and a little problem solving when encountering a problem.
Here’s the same thing in wenge. You can see the difference in the small end cut with the radius.
These pieces are all the same.
While this is primarily cut on the CNC, Kagan was the one directing the design. All decisions on the design came from him. We started the clock numbers in the mahogany next. At this point, we were both questioning how well the numbers would show up with finish applied. These were cut with a 90 degree V bit.
Here’s a somewhat major screw up. While making the profile cut I noticed the cut was way too close to the numbers so I stopped it during the interior cut. Luckily the cut was still shallow and the outside perimeter had not been cut yet. After looking back at the VCarve Pro design I realized I set the profile toolpath to cut on the wrong side of the vector. Ooops! This was actually a blessing in disguise. We flipped the piece over, cut the numbers with a 60 degree bit, and then cut the correct profile toolpath. The profile cut was in the correct location and the deeper numbers look much better. Here he learned that there are no mistakes, only happy accidents :) You can also see the slight bump-outs on the inside. These are to accommodate the updated radiused ends of the center field.
Kagan chopped through the tabs at the workbench. This is a simple task but it teaches him how to properly hold and use the chisel and mallet together.
On the computer, the vectors we made are 100% identical and fit perfectly together. The pieces are supposed to fit like a glove with the center half circles lining up. Just pushing them together by hand you can see that they don’t fit together. Looking back as I write this, my guess is that the poor fit by hand is due to wood movement because they fit great when pulled together with a clamp.
With the fit checking out we went to the router table to cut the tabs off with a flush-trim bit. Here Kagan learned how to use the router table.
For the plugs, I decided to make these cuts and have Kagan just observe. There was a lot of the blade exposed, no easy way to hold onto the material and a balancing act of keeping pressure against the fence while not trying to pinch the blade. The pocket for these pieces was 1/8” deep and I believe I cut these at 1/4” thick.
Ok…time to get ahead of ourselves and do stuff in the wrong order. After only rounding over the edges of the plugs we glued them in place. Bad move. We still needed to round over all the other top edges.
After realizing the order of operations error I came up with a solution to round over the other edges. I used a couple of pieces of 1/4” plywood to act as spacers. This would allow me to reference off the wide top face of the yin yang without the plug getting in the way. The only problem is I had to continuously re-position these pieces as I went around the shape. I did not attach them in any way. I just used downward pressure to stop them from sliding.
This also means we needed to raise the bit height above the normal roundover position.
With all of the roundovers done we can start the two-stage assembly. First, the yin yang is glued together with a quick setting glue.
Next, the yin yang is glued into the mahogany ring. This was the most stressful part of the build as I didn’t want the mahogany ring to split. We cut everything on the CNC to have a perfect fit. No allowances were added to the toolpaths. We used hide glue for this step as it won’t swell the wood and will also act as a lubricant while we gently hammer the material home.
We took our time to get the pieces in place. Here you can see the nice, tight fit. No gaps anywhere. It was perfect. When the piece was all the way down we were shooting for a 1/8” step at all pieces. The plugs are 1/8” taller than the yin yang and the yin yang pieces are 1/8” taller than the outer ring. This gives a nice 3D visual as you look at it from different angles.
No clamps necessary but we did let it sit for an hour or so to let the glue set up. In true yin yang fashion, we decided to make the clocks opposite of one another. The left side is dark on one and light on the other.
The rounded edges and different thickness are two subtle details that add a lot to the final look.
The last piece of the puzzle is cutting a pocket in the back for the clock movement. There is no standard here as not all clock movements are the same shape and not all clock movement shafts are the same length. If you purchase a short shaft you will need a deep pocket. I don’t recall any of the dimensions we used for the pocket or pocket depth as the movements we used were two that I have had in the shop for a couple of years.
To position the CNC for this cut Kagan held the clock with the bit in the center hole while I lowered the Z-axis. We also had to use a 1/2” plywood ring to elevate the clock so the yin yang wasn’t touching the table. This allows us to clamp it securely without it rocking. The XY location was then zeroed in the center of the clock and the pocket profile was cut. Rinse and repeat for the next clock. Here you can see how the backside of the messed up mahogany ring looks. It doesn’t matter though as it will spend its life against the wall. Kagan will keep this clock and the perfect clock will go to sifu.
For a finish, we used an oil wax mix. In true kung fu fashion; wax on, wax off! I don’t have any pictures of the clock mechanism installed as he was hesitant to install them before traveling. He had a 2-hour drive home and didn’t want the arms to get dinged up or bent. For size reference, the hands we used were 4-1/2” in length and covered all of the yin yang.
Yin Yang Clock CNC AND VECTOR FILES
These files are for a yin yang clock. I encourage you to create this file on your own as it is a good learning experience. However, I completely understand that some people understand how to make the vectors and would just like the convenience of getting the files. The vector files contain a collective vector with all pieces stacked as well as each vector separated for easy grabbing. Of course, the vector can be scaled to any size. We scaled it so that a 4-1/2″ clock hand kit would reach out to, but not touch, the number ring.
You will receive a download link containing a .zip file. The .zip file contains the following files:
Download links expire for security reasons. Download your files immediately and save them to your computer for your records. If you have any trouble contact me and I’ll remedy the situation.