When the sole of the plane body is not well-tuned, the hand plane will not be able to shave properly. This is why it is important to check the condition of the sole before using a Japanese hand plane, and tune it if necessary. Here we explain in detail everything you need to do to check and maintain the sole of your hand plane. You don't have to be a seasoned craftsman to follow these steps. Nor does tuning and leveling the sole have to be a daunting task.
In this article, we go over these important, easy-to-follow steps to help keep adjust the sole of your hand plane.
1: Methods for Checking the Sole
There are two ways to check if the sole is well-tuned.
The most common method is to check for two points of contact. When looking at the diagram, points C and D should be flat and parallel to each other. The points designated with lowercase letters a and b should be recessed by 1/10th of a millimeter from points C and D.
A more precise method is to check for three points of contact. To do this, check that points A, C, and D are flat and parallel to each other. Again, the points designated with lowercase letters a and b should be recessed by 1/10th of a millimeter from points A, C, and D.
2: Why Not Flatten the Entire Sole?
Making sure that the entire surface of the sole is perfectly flat is very labor intensive and not necessary.
As long as two points are flat and parallel to one another, the plane should work as intended. The most important points are the head and tail edges of the sole.
Another reason for having fewer points of contact on the sole, is that there will be less resistance when sliding the hand plane across the wooden board. By creating a shallow recess along the colored areas in the diagram, you can achieve this result.
Finally, the sole of the plane is quite sensitive and will change just by inserting and removing the blade. Because of this, it's easier to tune only the points that are affected by changes to the sole rather than the entire sole.
Before using the hand plane, point B should be shaved down because it will push outward once the blade is inserted.
As mentioned before, points C and D should be flat and parallel to each other.
3: Checking the Sole
When checking the condition of the sole, make sure that the blade does not protrude beyond the mouth. The edge of the blade should be recessed inside the mouth so that it is not quite showing.
You can check the flatness of the sole by using a straight edge with a notch cut out to protect the blade. A standard straight edge ruler or a steel square can be used for this process.
It is important to check the sole vertically, horizontally, and diagonally.
It's best to hold the hand plane and straight edge in front of a light source to see if there are any gaps between the straight edge and the sole.
Use a pencil to mark the five points along the sole, which will be used as sanding guides.
4: Flattening and Leveling the Sole
Attach 80-grit and 240-grit sandpaper to a very flat surface, such as glass. If you use a sheet of glass, we recommend a thickness of at least 8 millimeters.
Once the surface is ready, sand the sole of the hand plane until the pencil markings disappear. This will indicate that the sole is flattened, leveled, and ready to be tuned.
5: Tuning the Sole
Once the surface of the sole is flattened and leveled, use a sole flattening plane or a chisel with a blade wider than 30 millimeters to tune the sole.
First, shave the area between points A and B.
Next, shave the area between points C and D.
Once the sole has been tuned, check the results with a straight edge vertically, horizontally, and diagonally.
Finally, test the hand plane's performance on a piece of wood to see if the sole is properly tuned. If it is, you should produce beautiful wood shavings.
Check out our other articles for more great tips on how to care for and maintain your Japanese hand planes!