In order to be able to make Kumiko, you will need a few jigs. The amount and types of jigs highly depend on the pattern you want to make and the needed angles on the infill pieces as well as the type of grid you will make. In this article, I am gonna demonstrate the jigs for the Asanoha-pattern in a square grid, since it is one of the most common patterns and is a good starting point for beginners. I did start with it, too.
The Asanoha consists of a long diagonal infill piece (b), two smaller infill pieces ( c) and a small piece (d), that locks everything in place.
In order to fit perfectly together with the following angles on the pieces have to be cut:
a: 90-degree notch
b: 45-degree bevel on each side
c: 22.5-degree and 67.5-degree
d: 45-degree on each side
The grid can be cut in a few different ways. There are two common ways. With a Japanese pull saw and a narrow chisel or on the table saw with a jig that is similar to a box joint jig.
I like the table saw way. It is fast, accurate and repeatable. There is a downside. The thickness of your strips must match the thickness of your table saw blade. In the picture below you see my jig. The little pin sticking out of the fence is the same thickness as the grid.
Note: The triangular pattern (Mitsukude) is cut on a different jig, but with the same principle.
My preferred method of cutting the small bevels on the infill pieces is with a shop-made jig and a sharp Japanese chisel (I sharpened it 25 degree – Any angle would work but I found that 25 works best in terms of sharpness since durability is not really an issue when pairing only tiny pieces).
The jigs are essentially just a miter box with an adjustable stop, where the infill pieces stick out on one side and the excess gets cut by the chisel.
The jigs are made out of hardwood (I like oak for that). They are about 50mm (2”) by 45mm (1 ¾”) with an 8mm deep and 12 mm (½”) wide groove in the middle. The angles at the end match the angles needed for your pattern.
The stop is held at its place with a wing screw going in a threaded insert.
For the Asanoha I like to make only two blocks with an angle on each side. Therefore it is important which angle is on the same block with another. You want to have one jig with 45-degree plus 67.5-degree and the second with 22.5-degree plus 67.5-degree on the other end. This makes cutting the smaller infill pieces ( c) much easier since you are able to set both blocks with the 67.5-degree angle to different lengths. You can find more about how to cut the Asanoha pattern in my video below.
If you decide to build your own jigs make sure the angles are dead on and the stop is adjustable to the lengths you will need, depending on the grid size.
Here’s is how I build the jigs
I start by milling an oak board to 45mm (1 ¾”) thickness and then ripping strips slightly over 50mm (2”) off it. The next step is to send them through the planer one more time in order to get perfect 45mm (1 ¾”) by 50mm (2”) strips. For cutting the groove I use a flat-top table saw blade and make several cuts until the groove is about 12mm (½”) wide. A trick I like to use is rotating the strips 180 degrees between passes. Therefore you can make 2 cuts with each crosscut fence positions and it saves time setting up the fence.
After the groove is cut, I mill some more strips to fit the groove. They should have a nice friction fit. The height is not so critical. I let them sit a bit proud of the groove because that makes it easier to adjust them when cutting the pattern. They receive a 5mm (3/16”) slot in the center, where the wing bolt goes through.
The main body of the jigs gets a hole in the center. The depth, therefore, depends on the threaded inserts you use as well as the length of your screws. After installing the insert, I wipe on a single coat of oil to protect them.
Tataaaah finished are your Kumiko jigs and ready to build some awesome stuff.
Get your own jigs now
In my shop, I have finished jigs and Kumiko kits for sale. Give yourself a headstart and order one right away.