As per usual, the source is an email sent to me today. This time I will refrain from commenting as I've only recently managed to get all the egg off my face from the last episode.
So far we have looked at two different brands of bevel edged chisels one American and one English. Now we need to consider the Japanese. When these blades became popular in the West I was one of the first to advocate their use. This is because of the hardness of the blade and the sharpness of the cutting edge these ages were as sharp as the cold rolled steel blades that we were used to in the 1980s and 1990s the difference was that they held their edges between five times in eight times longer. we know this because I did a test in my workshop we took a piece of maple and ask an apprentice to pare back with a sharp blade and saw how much he could pare before the blade lost its edge. Not a terribly scientific test I know but it was the best we could do.
These blades are harder I believe, they are closer to the old-fashioned cast steel or crucible steel of the tools made before World War II. These were blades that had been heated and hammered. Their construction is laminated steel they have a hard surface which forms the cutting edge and the bottom of the blade laminated onto a soft steel which forms in the body of the tool. This laminating process requires heating and hammering.
Although these blades if you buy them from a small maker are absolutely superb in their edge holding capacity, I don't think they are the ideal furniture makers chisel. These are carpenters tools made to be struck with a hammer designed to be used on large sections of softwood. Furniture makers need more delicate tools than the standard Japanese chisel. I do have a few of these in my toolbox and I will continue to use them but I mix them with and lighter Western blades.
A problem we have seen is the disappearance of a small highly skilled Japanese blacksmith. Most of the chisels imported to the west are made now in small factories and the quality is not as high as we are used to getting from the old master blacksmith's. When I was in Tokyo I was taken to meet a blacksmith, his workshop was probably smaller than a one car garage. He worked there with his 83-year-old father. I asked him to sell me a marking knife he asked my name and then proceeded to carve into the handle the symbols that indicated that this knife is mine. Then he turned to his father held the blade to his forehead and showed his workmanship to the old man. And the old man gave an appreciative grunt. Dad was the quality control department, the blacksmith was asking the old man "have I upheld the standards and values of your lifes work," the old man was acknowledging his son's achievements and congratulating him on his workmanship without giving him an inch more. All in a grunt.