Cutting devices and carbide cutting knife with a lateral ring

摘要

Blades with tungsten carbide cutting edges have a surface at a relief angle and a surface at a reverse angle at the periphery. A smooth crown is provided at the intersection of the surfaces. The crown will contact and be included within an overlap of a cooperating offset steel blade. The relief angle may be between about 1 and 3 degrees and the reverse angle about 1/4 to 1 degree. The crown may have a finish of about 2-6 micro-inches. The contact between the blades during operation provides a polishing or self-sharpening effect. The tungsten carbide blades are used in rotating shear wheel devices and scissor cutting devices to cut tire cord fabric.