The Role of the Katsura (Chisel Hoop) & How to Adjust It
Welcome to our tutorial on using Japanese chisels, where we'll explore the role of the Katsura (chisel hoop) & how to adjust It working with it.
We'll break it down step by step so that it's easy to understand and put into practice.
1: What is Katura?
The top of the striking chisel handle has an iron hoop.
We say it "Katura" in Japanese.
Its primary function is to reinforce the wooden handle to prevent splitting when struck.
New Japanese striking chisels need to have the hoop adjusted.
If you skip the katsura-setting process and start using the chisel as-is, the hoop may overextend and cause 'flaring.'
As a result, it may eventually crack or become loose, no longer fitting securely onto the handle.
To prevent flaring, start by adjusting the chisel hoop using the Katsura Otoshi method, also known as "adjusting the chisel hoop."
The purpose of this process is to make sure the hammer strikes the wood directly, not the hoop.
This helps protect the katsura and extends the life of both the hoop and the chisel.
During katsura otoshi, the wood fibers at the top of the handle are gently expanded so they slightly cover the lower edge of the hoop.
This way, when the chisel is struck, the force is absorbed by the wood, reducing wear and preventing damage.
Regularly, adjusting the chisel hoop can prolong the lifespan of your chisel handle.
2: How to Adjust Katsura
Start by gently tapping the chisel hoop with a mallet to remove it.
Using a nail punch and mallet can make this easier.
Remember the orientation of the chisel hoop when removing it. The side that fits into the handle is wider, while the striking side is narrower.
If your chisel hoop has become flared from use, use a metal file to smooth out the inside and remove the flare.
Bevel the inner side to widen the insertion end.
Shape the handle slightly to align with the chisel hoop and eliminate any unevenness, but be careful not to overdo it.
Insert the chisel hoop back onto the handle by hand and strike it evenly from the top using a mallet.
We will lower the chisel hoop 2-3mm on the handle.
Strike the edges of the chisel hoop, rotating it for evenness.
Once the chisel hoop is set 2-3mm lower, flatten the protruding edge of the handle over the chisel hoop using a mallet.
Rotate and tap gradually to spread the wood outward.
With that, the chisel hoop setting is complete.
Adjusting the hoop, as demonstrated, helps prevent handle splits and reduces vibration, making the tool more comfortable to use.
Check out our other articles for more great tips for using Japanese chisels!
