The first time my son showed me a Kumiko piece he had made, I was hooked. Upon researching Kumiko, and with my experience as a junior high school wood shop teacher, I knew what I needed to do. I had to make Kumiko by hand.
In addition I completed three pieces by hand, all xmas gifts. The finish projects were not bad. Below is what I would include as reference material for myself, in the construction of any Kumiko project.
Projects Completed By Hand
A quick note. The Kumiko strips only were cut on machines. Furthermore in Japan these strips would also be cut by hand. All other cuts were completed with hand tools.
Generations Pieces
There is over 600 Kumiko pieces in the three projects above. In addition each piece has been hand cut in some manner. Furthermore eighty percent of the pieces in the three projects were planed at both ends at various angles.
Explanation Of Pieces
On the left (Generations #1) is a generations family tree. Four Asanoha patterns on the left represent grandparents. Two Asanoha patterns in center represent parents and the one Sekura pattern on the right represents a grandchild. In addition this piece could also be interpreted as parents, children and grandchildren.
In the center of the piece (Generations #2) is a generations family tree. Four Asanoha patterns on the left represent grandparents. Two Asanoha patterns in center represent parents and the two Sekura patterns on the right represents a grandchildren. In addition this piece could also be interpreted as parents, children and grandchildren.
The piece on the right (Generations – Grandchildren) is a generations partial family tree. Three Sekura patterns represent grandchildren. In addition this piece could also be interpreted as any three family members.
Process Of Cutting
After constructing the Kumiko pieces by hand I discovered the process would have to be both hand work and machine work. Furthermore I would not discourage anyone from doing all of this work by hand. In addition it is a great learning experience.
- Combined work processes save time
- Quality square cuts increases with using machines
The biggest issues when cutting by hand are keeping pieces square and cutting pieces square.
Planning The Piece
There is one term I constantly think of when building Kumiko. Square! It is so important that all cuts be as square as possible. Furthermore this become problematic when cutting by hand. in addition with practice, your cutting will improve but it takes a lot of practice.
Draw A Plan
Drawing a plan with all dimensions is crucial. If necessary for larger pieces draw your plan to scale. Furthermore this is going to be critical when laying out your frame and cutting pieces. In addition it is also very helpful when trying to determine the amount of material you will need.
As well you can plan out your cutting schedule for all pieces.
Dress And Plane The Lumber
Dress and plane all lumber needed for your Kumiko piece at one time. This will ensure all dimensions are the same. In addition this would also include any other wood species you use in you piece. Furthermore it is essential that all lumber be of the same planed dimensions.
- Dress Pine lumber, plane one face and joint one edge.
- Thickness plane Pine to 12mm (Mikomi)
Using A Sled To Cut Your Lumber
Although Kumiko can be cut on the table saw without the use of a cutting sled, it is a good idea to use one.
In addition there are many video tutorials on building sleds on YouTube.
A sled is a device you build that fits your saw. furthermore it can be used to cut all angles for your Kumiko.
Using the sled you can cut any angle you wish. The typical angles used in Kumiko are 45, 22.5, 30, 60 and 67.5 degrees. We will also use jigs we make to those angles in our pattern pieces. We will cover those later.
Cutting Notches For Lap/Overlap Joints
Before cutting individual Kumiko pieces, check to see if you can mass cut.
Most Kumiko pieces will have a number of Lap/Overlap joints where the framework fits together. The framework can be in a diamond shape or a square framework.
Depending on the design of the piece, mass cutting of notches can be done.
A diamond grid framework is easier to mass cut, as opposed to the Generations pieces above. Assuming you have dressed and planed your lumber:
- Square on end and cut lumber to length.
- Determine what length and width of lumber you need to mass cut all of your lap notches.
- Mark the board where you will cut notches.
- Set your blade to half the depth of the material, in this case 6mm.
- Cut all notches.
- Rip Kumiko strips from your notched board on table saw.
If you are doing a piece like the Generations piece above you can mass cut as many of the lap notches as possible. You would then cut individual pieces with lap joints.
Cutting Kumiko Strips And Storing
Cutting all Kumiko strips needed for a piece will be cut by machine. In this example we use Pine for the Kumiko strips. For a diamond grid framework, after cutting all of the lap joint notches you can mass cut the Kumiko strips.
Reminder: The importance of a plan comes into play when cutting materials. From your plan, if drawn to scale, you can determine the lengths of each piece needed. You can determine and layout your lumber to get the most effective cutting and save on materials.
Reminder: The importance of dressing all of your lumber at the same time is crucial. If you need to leave the project to finish later you know that all of your lumber is dressed to the proper dimensions for future use.
TIP: I made cases to store my cut Kumiko pieces that I have yet to use. First, It keeps it out of the sunlight so it doesn’t discolor. Secondly it keeps it all flat and straight so that it doesn’t warp.
- Cut Kumiko strips for the patterns to desired thickness (Mistuke) 1/8 inch or 3mm which will work. In some pieces the framework may have a thickness (Mistuke) of 1/4 inch. It will still have a width (Mikomi) of 12mm.
Jigs Needed To Make Kumiko
In order to cut Kumiko pieces to the correct angles you will need jigs.
Jigs are normally made in the shop from a solid piece of lumber. Furthermore there are also many videos on YouTube showing you how to make them.
Cutting your Kumiko to the exact length will allow for better fits when cutting angles.
Typical jigs would be made for 45, 22.5, 67.5 and 60 degrees.
Tools Used In making Kumiko
Once you have your pieces cut and assembled for the framework, handwork will be needed to assemble the rest of your piece. Furthermore you will need some hand tools listed below.
- Block plane: (Optional) This can be used to plane pieces to the correct angles with jigs. It is very important to have sharp tools. Planer blades need to be sharpened on a regular basis. Videos on sharpening planer blades can be found on YouTube.
- 1 1/2 Good Wood Chisel: Again having sharp tools is essential. Kumiko can be cut with a larger chisel (1 1 /2″). I found it easier cutting Kumiko on the jigs with a chisel. There are many videos on YouTube on sharpening chisels.
- Dozuki Japanese Hand Saw: Even though you cut most of your pieces on the table saw you will still need to cut pieces by hand. The Dozuki is the best saw for this.
- Marking Knife: A good marking knife with one beveled edge. This allows the blade of the Dozuki saw to have a good cutting edge to start the cut.
- Small Adjustable Square: I use a small tri square that can be adjusted. Square every piece for a better result.
Assemble The Kumiko Frame
Whether you build a piece using a diamond grid or a square grid, as show at left, you need to build this and keep it square.
Mass cutting all of your notch overlap joints will help in keeping it as square as possible.
In addition this will allow you to construct your patterns and have them all come out the same.
Assemble The Patterns
Once you have your grid assembled you can now start constructing the patterns.
Start in one section and complete that section. In addition you can use these measurements to cut all of your pieces of the same size.
With the jigs you can mass plane your angles on all of the pieces you will need.
Side Note: You may have to adjust your jigs for some pieces. Furthermore, even though you were as carful as possible some of the pieces for the patterns may be slightly smaller or larger.
In Summary
- Hand cutting all pieces may cause some pieces to be out of square.
- Doing a Kumiko piece by hand is a great learning experience.
- Mass cut as many pieces as possible to save time and material.
- Dress and plane all lumber for a particular project.
- Cut Kumiko strips as needed.
- Store unused Kumiko so it doesn’t discolor or warp.
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