Introduction: Hexagonal Kumiko Table Saw Sled
Let's make an easy table saw sled for making hexagonal kumiko.
Step 1: Cut the Sled Parts
Cut out the base (22" long x 14" wide) from a sheet of plywood or MDF. You can definitely use any sheet material you want for your sled, but I would choose something stable for the base.
Exact dimensions should probably be based on your table saw, but I went with something roughly 22 inch long by 14” wide. The 22 inch length spaces out the fences, giving you the ability to do a number of operations on the sled, and the width allows for good support for the strips.
Cut out the fence parts. These should be 1-2" wide and as long as the base is wide (for me, this would be 14"). You will need two fences to hold the sled together, and I generally like to have a fence that is 1-1/2" thick (two laminated pieces of plywood) for rigidity.
At this time, also cut out the material for the angled fences. I choose to make them 1-1/2" wide, but this is arbitrary. You technically only need each fence to be about six inches long, but if you go longer you'll have more support for the kumiko parts.
Step 2: Laminate the Front and Rear Fences
Glue together the two pieces that make up both the front and rear fences. These will need time to dry, so do this before you start working on the base assembly.
Step 3: Make the Runner
To make the runner, I suggest either rift-sawn or quarter-sawn scrap. If you’re using quarter-sawn material, you will want to orient the grain so it’s vertical inside the miter slot. This ensures that you minimize any movement the wood might undergo. Rift-sawn material spreads out radial and tangential movement over both faces, making it very stable.
Although most miter slots are around three quarters of an inch, for a critical fit like this one, I take my time to measure accurately with calipers. This isn’t strictly necessary — you can just sneak up on a good fit slowly and methodically as well.
When you get a friction fit — where the runner will slide but stop when you stop pushing — trim the height of the runner so that it's just about 3/8" tall and you're ready for the next step.
Step 4: Create a Dado Channel for the Runner
For the remaining steps, I am going to need to reference one edge repeatedly, so I make a note for myself on the side. It’s not critical which side, but it will be the only side that touches the fence in future steps.
From that reference edge, I measure where I want to place a shallow dado for the runner. Again, where exactly that is doesn’t matter, but make sure it’s not right at the edge so you can get a good, solid fit for the runner. I chose a distance of roughly two inches away from the edge.
Since I cut my runner to about a half inch thick, I am only going to make an eighth inch dado in the base.
To make the actual cut, you can use a router, a dado blade, or just take multiple passes with the table saw blade like I did. Like with the runner, I’m stopping shy of the other end of the groove; I want to sneak up on the fit.
When the runner fits snugly into the channel, you can glue it in with wood glue and drill and countersink for 3/4" screws to hold it into place.
Step 5: Make the Key Groove
With the basic sled base assembled, I started laying out where a groove would go to hold the “keys” — you’ll see how the key works a little later. I started by outlining where the blade touched the base, but I quickly realized that it was a better idea to just cut the kerf. I’m going to be setting the exact pitch with this groove, so having an accurate kerf was important. I sawed just a couple inches into the board for now to establish the main kerf of the sled.
Now you can measure from that kerf to where you want the key. I’m setting the pitch on this sled to be 2 inches. Notice that it’s not two inches between the two kerfs, but the distance between the left side of the first kerf and the left side of the next kerf. Pitch can be measured from the left, right, or center, but it always includes one full kerf in its measurement.
I reset my blade height to a quarter inch and, against the reference edge, sawed the key groove all the way across the sled.
Step 6: Attach the Front and Rear Fences
Like a traditional crosscut sled, the front fence won’t be used as a reference, so I just made it reasonably square to the reference edge. I secured it with four screws, being sure to avoid the main kerf area in the middle. You can glue it to the base as well, but it's not completely necessary.
The rear fence (the one you will push against) is also not used as a reference on this sled, so you can attach it as you did the front fence. I spent just a little extra time to get it close to square, but I didn't dial it in like I did on my normal cross-cut sled.
Once the front and rear fences are attached, you can extend the main blade kerf all the way through the sled.
Step 7: Attach the Angled Fences
The fences that matter most on this sled are the angled fences. They need to be exactly 60 degrees off of the reference edge.
Start by cutting 30 degree angles on each end of the two angled fences. I used a miter saw, but you can use a variety of tools to do this. Then drill and countersink a hole about an inch in from each end.
Now put the sled into the miter slot on the table saw, then slide the fence up to the reference edge. Using your 30-60-90 drafting triangle, position the triangle with its 60-degree side up against the fence, and bring the angled fence up to the hypotenuse of the triangle. Secure it with one screw, then micro-adjust it to get a perfect 60-degree angle from the fence, and secure the fence with a screw on the other end.
Repeat with the other fence oriented in the opposite way, and be sure that the fences don't make contact with each other so you can get a piece of kumiko through the gap.
Secure the fences with a few more screws and you're basically done.
Note: You can absolutely use a bevel gauge and an angle reference block to get this angle if you don't want to buy a drafting triangle — I just don’t have a good reference for 60 degrees except this triangle.
Step 8: Make a Registration Key
The key is a piece of kumiko that will set the pitch as you cut cross-laps.
Start with a piece of hardwood that is a half inch thick and at least an inch wide. Set the fence to the thickness of the blade, and cut a strip. If you need a better explanation of how to do this, I've made a YouTube video in the past describing this.
Test the thickness. If it's loose, try again. If it has a nice friction fit (like the runner before), it's perfect.
Now that the key’s done, just slide it up against the fence and you can start making hexagonal kumiko.