FAQ

Most Japanese hand planes are made at 8/10 slope. Strictly speaking it's a bit different, but here, think of this "slope" as the angle between the bed on which the blade rests on, and the sole of the plane body. 

This 8/10 slope (approx.38.6 degrees) can cover from softwood to hardwood, but it’s not universal. This is just like there is no one-size-fits-all solution in this world. So some people custom order special slopes such as 7/10 or 9/10 to deal with super soft and hardwood.

The size of Japanese planes is tricky. While normal size planes are referred to by the Japanese imperial measuring system, such as 1.4sun or 1.8sun, smaller planes are referred to by the metric system, such as 48mm. What makes this even more tricky is that these sizes do NOT represent the actual size a particular plane shaves. So in our shop, both the nominal size and the actual planing size (size of the mouth opening) are displayed for your better understanding.

Some higher-end models of planes have a special mouth opening called a tsutsumi. Tsutsumi is done to make the mouth opening look narrower. This is because a plane with a narrow mouth opening is considered “cooler”. To be honest, Hisa personally finds very little practical benefit in the tsutsumi. It sometimes limit the range of the blade's bevel angle. Therefore, removing the tsutsumi can be an option if you don’t like it. 

Most Japanese hand planes commonly used today have a chip breaker. Chip breakers prevent tear-out from occurring on the timber surface. According to some books, chip breakers first started to be used more than 100 years ago, in an attempt to imitate those of Western hand planes. While chip breakers are usually mass produced, for high-end models, the same blacksmith who makes the blades also makes chip breakers himself. Such chip breakers are engraved with the same logo as the blade.

Before the introduction of chip breakers from the West, there were no chip breakers in Japan. At that time, straight-grained wood was readily available, so tear-out was not a frequent occurrence. Even without chip breakers, it was possible to finish the surface clean and smooth. Unfortunately, today, it is not so easy to get a piece of timber with straight grain, so, a plane with no chip breaker may not be very practical today.

The blade will gradually become loose as you use it. This is probably because the wood around the side grooves gets compressed by the blade as you repeatedly push it in and pull it out over time. The easiest solution is to attach a postcard to the bed with some glue. We also have an alternative solution using rice glue (this solution can be found in our premium tutorial video courses).   

The mouth opening will get wider and wider as you continue to re-tune the sole. A hand plane with a mouth opening that has widened much can no longer prevent tear-out. The solution for this is to fill the widened mouth with another piece of timber (this solution can be found in our premium tutorial video courses). 

When the plane is still new, it is difficult to see the gap between the blade and the chip breaker because the mouth opening is narrow. However, you can hold the plane up to a light, tilt it forwards or backwards, or look into it at different angles to find the best angle. We are sure you can find the best angle.

A plane body is delicate. Too much or too little moisture can cause problems. So it is a good idea to leave it untouched until the wood gets used to its new environment and the moisture inside is somewhat stabilised. At this time, wrapping the body in newspaper will prevent the body from badly losing its condition. 

It can be adjusted by tapping the chip breaker pin inward or bending it outward with a flat head screwdriver. However, these are only first aid solutions. If you want to fix it properly, you need to grind off the bottom (the side that touches the chip breaker) of the chip breaker pin, or glue a postcard to the bed, or use the rice glue solution, which is explained separately.