How to Adjust the Chip Breaker of Your Japanese Hand Plane
Are you familiar with the function of a chip breaker and how to adjust it on your Japanese hand plane? When properly set, the chip breaker prevents issues when planing against the grain, ensuring the fibers are cleanly cut rather than torn or ripped from the wood's surface.
In this guide, we'll explain the role of the chip breaker and how to adjust it for the best results. If you're not familiar with the parts of the plane, check out our article How to Adjust the Blade of Your Japanese Hand Plane for an in-depth breakdown of each component.
What Is a Chip Breaker and Why Is It Important?
Let's take a closer look at the chip breaker (also known as uragane) and the important role it plays in achieving a smooth woodworking finish. The chip breaker is an essential component that helps ensure your planing process is as efficient and precise as possible, especially when working against the grain.
What Is a Chip Breaker?
The chip breaker is a blade positioned directly behind the plane's main blade. Its purpose is particularly beneficial when planing against the grain.
When properly adjusted, the chip breaker stops the shavings from being torn or damaged, providing a clean, smooth cut. Planing against the grain without a chip breaker results in uneven cuts, leaving splintered surfaces or gouges in the wood. On the other hand, using a properly adjusted chip breaker will yield a much cleaner finish.
Check out our YouTube video to see the difference between planing with and without a chip breaker.
With a chip breaker set correctly while planing against the grain:
Without a chip breaker while planing against the grain:
How the Chip Breaker Works
To fully understand how the chip breaker works, it's important to grasp the basic mechanics of the Japanese hand plane.
If you'd like to explore the fundamentals of using a Japanese hand plane, including the proper techniques, be sure to read our guide on How to Use a Japanese Hand Plane: Planing & Finishing Guide.
In simple terms, here's how the plane works:
・The main blade (kanna-mi) engages the wood, digging into the surface.
・As you push the plane forward, it removes the shaved wood, creating a smooth surface.
The chip breaker's job is to sit just behind the plane's main blade, precisely aligning its edge to prevent the main blade from cutting too deep. This ensures an even, controlled shave, especially when planing against the grain. Without a chip breaker, the main blade can dig too deeply into the wood, resulting in an uneven, rough cut with torn or chipped areas, as shown in the image above.
How to Adjust the Chip Breaker
Now, let's go over how to properly adjust the chip breaker to get the best performance out of your Japanese hand plane.
Before You Start: Check the Condition of Your Plane
Before you adjust the chip breaker, it's important to inspect the condition of your plane.
・Blade Sharpness
Ensure that the main blade is properly sharpened and free from chips or damage. A sharp blade is the foundation of a clean, smooth cut.
・Cleanliness
Check that there is no dirt, resin, or wood shavings left on any of the plane's parts. A clean tool ensures an accurate adjustment.
Once you've checked these two points, you can proceed with the chip breaker adjustment to keep your plane performing at its best.
Adjusting the Chip Breaker
Adjusting the chip breaker correctly is essential for getting the best performance from your Japanese hand plane. The most common adjustment involves setting the distance between the chip breaker's edge and the blade's cutting edge. Here's a straightforward way to adjust it for optimal results:
Step 1: Align the Chip Breaker with the Main Blade
Begin by gently placing the chip breaker on top of the main blade. Lightly tap the chip breaker with a small hammer to fix it in place. The goal is for the edge of the chip breaker to be about the thickness of a human hair from the edge of the main blade. Be careful not to tap too hard—this adjustment should be subtle.
Step 2: Test the Shavings for Shape
After each adjustment, test the setup by planing a piece of scrap wood. If the shavings come out smooth and consistently straight, the chip breaker is properly aligned. If the shavings are uneven or inconsistent, the chip breaker may be too loose or too tight.
Shavings with a properly functioning chip breaker:
Shavings when the chip breaker isn't working correctly:
Shavings when the chip breaker is set too aggressively:
Step 3: Set the Gap Between the Chip Breaker and the Blade
Using a small hammer, gently tap the top of the chip breaker to move it closer to the edge of the main blade. Continue tapping until the gap between the chip breaker and the blade is very small—approximately the width of a human hair. This precise gap is crucial. It allows the chip breaker to push the wood fibers down just before the blade cuts, preventing the blade from cutting too deeply and minimizing the risk of tear-out. The result is a smoother surface.
Step 4: Avoid Overextending the Blade
When tapping the chip breaker, be mindful of the main blade's position. The main blade may shift during the adjustment, so it's important to check its position regularly. If necessary, readjust the blade to ensure it is set properly.
Step 5: If the Chip Breaker Exceeds the Blade's Edge
If the chip breaker extends even slightly beyond the edge of the main blade (even by the width of a hair), the result will be tangled shavings, and the plane will not cut properly. In this case, you will need to remove both the main blade and the chip breaker, then readjust their positions.
To remove the blades, hold the plane body in one hand and use your fingers to secure both the main blade and chip breaker. Gently tap the top of the plane's body to release the blades. Once removed, reposition both the chip breaker and main blade, then reassemble the plane.
Pro Tip
When adjusting the chip breaker, keep in mind that minor adjustments can make a significant difference. Even a slight misalignment can affect how easily the plane glides and how smooth the finish will be.
If you're unsure, adjust the chip breaker incrementally and test it frequently. Making small adjustments instead of over-correcting all at once will reduce the risk of mistakes and ensure more precise results.
Adjusting the Shape of the Chip Breaker (Uragane)
The ideal condition for a chip breaker is one where there is a slight gap and both ends are perfectly attached to the main blade. If you notice the chip breaker does not align correctly with the blade, it will need to be adjusted to ensure a proper fit.
How to Adjust the Shape of the Chip Breaker
If the chip breaker's edge doesn't align perfectly with the main blade, gently tap the ears of the chip breaker with a hammer to reshape it. Carefully and slowly adjust it until it fits snugly against the blade. This step ensures that the chip breaker and the blade are properly aligned, improving the efficiency of your planing and resulting in a smoother surface.
Ensuring Safety During Chip Breaker Adjustment
Adjusting the chip breaker requires careful attention. Below are some important tips to ensure safety and optimal results:
・Work Slowly and Methodically
There's no need to rush. Tap gently and make small adjustments, testing the results with a test shave after each change. Moving slowly ensures you can properly set everything up and avoid mistakes.
・Be Mindful of Your Hands
Keep your fingers away from the blade, especially when tapping the chip breaker. It's easy to get focused on the adjustment, but your hands' safety should always be a top priority. When using the hammer, make sure not to strike your fingers accidentally.
For More Tips on Maintaining Your Japanese Hand Plane
