A measuring apparatus for bevel angle of cutleries has been devised by the writer. There is the Honda's paper-cutting sharpness tester which measures the durability as well as the initial sharpness of the edge. As far as the durability is concerned, the shape of bevel is of great importance. In general, the bevel is not a simple geometric wedge but a surface of complicated curvature. Using the new apparatus, the curvature and the edge along the whole length of the bevel can be examined by simple and easy manipulation with reflection of a narrow beam of parallel rays of light directed to the bevel. Safety razor blades have so far been examined revealing many characteristics hitherto unobserved.
