February 3, 2025
Interesting facts
Construction of a Japanese plane
The Japanese Plane – History and Aesthetic Appreciation
Planes appeared in Japan much later than in Europe, around the year 1500. Until then, surfaces were smoothed with a so-called lance plane, the yari ganna. The lance plane, with a short slightly curved blade at the end of a long handle, is pulled over the wood with both hands. It leaves a smooth but slightly ribbed surface. The models for a plane with a fixed iron and straight edge are believed to have originated from China and Korea. With them, it became possible to truly work surfaces flat. Planes in Japan have only been equipped with chip breakers since the end of the 19th century, likely inspired by Western tools.
In its reduced cubic form, the traditional hand plane represents many examples of Japanese design. Despite its primitiveness, it surprises with high performance. It consists of only two, at most four parts: the low plane body and a thick, slightly conically shaped plane iron, and possibly a chip breaker and a support. There is neither a strike button nor a hand guard; the Japanese plane operates without "horns" and does not have fine adjustment via screws. Its handling, especially the adjustment with a hammer, usually requires longer habituation and practice; the best results are achieved with it on softwoods. Thanks to its low height and center of gravity, it sits firmly and does not wobble. You work with the Japanese plane much closer to the wood than with its Western relatives.
Wood Selection
In Japan, the wood of the Kashi tree, an evergreen broadleaf tree, is traditionally used for making planes. Due to its high hardness, the plane sole hardly wears out. Thanks to its high toughness and split resistance, the plane body hardly tears. Finally, the relatively light color of the wood makes sense, as the dark plane iron is always easy to see due to the contrast. Therefore, use a blank made of Kashi or take a particularly well-seasoned local wood with similar properties, such as stress-free red beech, white beech, or fine-grained maple wood.
Particular care is required in selecting the material. It should be as straight-grained and stress-free wood as possible, dried for at least one to two years. The "left" side, that is, the side facing away from the heart, forms the plane sole, while the "right" side faces up. If the material is dried again, the sole will become slightly hollow. The wood fibers either run parallel to the plane sole or are slightly inclined towards the iron. Such an inclination allows the plane to glide better and its sole wears less. The two ends of the plane body, called dai, are referred to as "atama" or head and "shiri" or butt.
Note: The work steps were documented in the Inomoto workshop in Sanjo, which specializes in the production of smoothing planes. The templates for the sketches of the individual work steps also come from Mr. Inomoto.
Planes appeared in Japan much later than in Europe, around the year 1500. Until then, surfaces were smoothed with a so-called lance plane, the yari ganna. The lance plane, with a short slightly curved blade at the end of a long handle, is pulled over the wood with both hands. It leaves a smooth but slightly ribbed surface. The models for a plane with a fixed iron and straight edge are believed to have originated from China and Korea. With them, it became possible to truly work surfaces flat. Planes in Japan have only been equipped with chip breakers since the end of the 19th century, likely inspired by Western tools.
In its reduced cubic form, the traditional hand plane represents many examples of Japanese design. Despite its primitiveness, it surprises with high performance. It consists of only two, at most four parts: the low plane body and a thick, slightly conically shaped plane iron, and possibly a chip breaker and a support. There is neither a strike button nor a hand guard; the Japanese plane operates without "horns" and does not have fine adjustment via screws. Its handling, especially the adjustment with a hammer, usually requires longer habituation and practice; the best results are achieved with it on softwoods. Thanks to its low height and center of gravity, it sits firmly and does not wobble. You work with the Japanese plane much closer to the wood than with its Western relatives.
Wood Selection
In Japan, the wood of the Kashi tree, an evergreen broadleaf tree, is traditionally used for making planes. Due to its high hardness, the plane sole hardly wears out. Thanks to its high toughness and split resistance, the plane body hardly tears. Finally, the relatively light color of the wood makes sense, as the dark plane iron is always easy to see due to the contrast. Therefore, use a blank made of Kashi or take a particularly well-seasoned local wood with similar properties, such as stress-free red beech, white beech, or fine-grained maple wood.
Particular care is required in selecting the material. It should be as straight-grained and stress-free wood as possible, dried for at least one to two years. The "left" side, that is, the side facing away from the heart, forms the plane sole, while the "right" side faces up. If the material is dried again, the sole will become slightly hollow. The wood fibers either run parallel to the plane sole or are slightly inclined towards the iron. Such an inclination allows the plane to glide better and its sole wears less. The two ends of the plane body, called dai, are referred to as "atama" or head and "shiri" or butt.
Note: The work steps were documented in the Inomoto workshop in Sanjo, which specializes in the production of smoothing planes. The templates for the sketches of the individual work steps also come from Mr. Inomoto.
Marking
Hold the chisel with your right hand. Press several fingers of your left hand (depending on the width of the chisel) against the flat side of the chisel at the bottom of the bevel, so that its surface rests stable on the sharpening stone. You can support the chisel from below with your thumb. The best edge is achieved when the edge is held perpendicular or at an angle of up to 30° to the direction of sharpening.
In contrast, for narrow chisels, where the edge is narrower than the length of the bevel: Hold these chisels with your right hand as far back on the handle as possible and move them back and forth while sharpening with the edge. It is perfectly legitimate to use a sharpening guide, which is strongly recommended for beginners. Sharpen until a fine burr forms on the edge.
Now - but not before - you can proceed to honing the edge. Use a sharpening stone with a grit between 3000 and 8000 and work on the bevel and flat side alternately just like in the previous sharpening process. The burr will fall off, and the bevel and flat side will become increasingly shiny and thus sharper as the honing process progresses.
Make sure to carefully dry the chisel after sharpening and lightly oil it before storage to avoid corrosion. Then you will enjoy your precious tool for a long time.
Markieren Sie zunächst die Position des Mauls an der Unterseite (Sohle) des Hobelkörpers. Die Länge wird so aufgeteilt, dass 60% vor dem Hobeleisen liegen und 40% hinter ihm. Riss A.
First, mark the position of the mouth on the bottom (sole) of the plane body. The length is divided so that 60% is in front of the plane iron and 40% is behind it. Crack A.
Place the plane body on its side and mark the angle of the plane iron. Japanese smoothing planes used for softwood have an angle of 38-40 degrees, while a slope of 42 degrees is recommended for hardwood. The Japanese plane maker marks the angle with his carpenter's square. You can also use a protractor. Crack B.
Now place your slightly conical plane iron on the side of the plane body. The mirror side of the plane iron is against the crack B. Position the plane iron so that it is only about 80% inserted into the plane body. The iron should sit firmly/tightly later.
Now also score the back of the plane iron on the side of the plane body. Score C.
Now transfer the foot point of crack C to the plane sole, crack D.
Now drop a perpendicular from the foot point of crack C on the flank of the plane body to crack E.
Transfer this crack from E also to the top of the plane body, crack F. 24 mm towards the "rear" will then be marked on the top as crack G.
Then the "thick" end of the plane iron is marked on the top side of the plane body, cracks H and I. Special care must be taken with these two cracks. If the groove for the plane iron is chiseled too wide, it will sit loosely and the plane will be unusable. You would then have to go through the trouble of packing it out.
Check your plane iron now and measure how deep the back of the iron is. The concave curvature called "shakumi" varies depending on the blacksmith and the iron, usually the value is around 0.5 mm.
Now score this curvature of the iron at the top of the plane body, crack J.
Mark on both sides of the plane body the front slope of the chip box, this will make drilling and re-chipping easier later, crack K. This crack meets at the sole exactly at the foot point of crack C.
Place the plane iron now on top of the plane body and transfer its width in the area of the grooves, cracks L.
Now place the chip breaker centrally on the plane body and also mark its position, crack M. There should be about half a millimeter of space between the chip breaker and crack M, so that the flap later has some play in the chip box.
Working out
Mark on the top of the plane body with a marking gauge and scribing knife the boundary of the chip box. Extend the short marks M to the scribe lines N.
Finally, the width of the plane iron and the chip box is also scribed on the sole of the plane body. For this, mark the scribe lines L and M.
Finally, the width of the plane iron and the chip box is also scribed on the sole of the plane body. For this, mark the scribe lines L and M.
Wir beginnen damit, das Hobelmaul an der Sohle des Hobels einige Millimeter tief auszustemmen.
We start by chiseling the mouth of the plane a few millimeters deep at the sole of the plane.
Caution, the mouth is angled before the blade, that is, on the side facing the "rear" of the plane body.
At the top, the chip box can now be pre-drilled with the column drill and then chiseled out.
When chiseling, you can align your eye over the cracks C and K that you have marked on the sides of the plane.
Tuning
The grooves for the conical plane iron are now cut with a narrow saw and then carefully chiseled out with the hole chisel.
Mark the position of the abutment pin on one cheek of the plane body. This pin will be recessed at two-thirds the height of the plane body. When marking the position, the chip breaker should be set back about 6 mm from the sole; otherwise, the chip breaker will not fit snugly later on.
Mark the position of the abutment pin on one cheek of the plane body. This pin will be recessed at two-thirds the height of the plane body. When marking the position, the chip breaker should be set back about 6 mm from the sole; otherwise, the chip breaker will not fit snugly later on.