Studies on Quantification of Sensuous Sharpness and Mechanical Sharpness of Wood Cutting Tools. V. Effects of Cap Iron on Chip Deformation and Surface Quality of Workpiece in Planing of Wood against Grain with a Japanese Hand Plane

摘要

Japanese hand plane is one of the basic tools used by junior high school students for woodworking. The invention of the Japanese hand plane with a cap iron was the most important advance in the history of woodworking tools in the last one hundred years. It has seemingly a very simple mechanism, but it demands a lot of skill to adjust the each part of the plane. Therefore, it is one of the difficult tools for a general amateur, a junior high school student, a junior high school teacher, and an unskilled woodworker. In this study, in order to make clear the effect of distance between knife edge and cap iron edge (ℓk) and edge angle of the cap iron (βR) on the working degree of the cap iron, and in order to fing the optimum condition for setting the cap iron of the plane, the planing tests with various Japanese hand planes were performed. Chip deformation and surface quality were observed and estimated in planing of wood against the diagonal grain and with the interlocked grain, and characteristics and sharpness of various planes used in this study are discussed.