Abstract: The invention relates to a method for manufacturing a sheet metal tool that is not planar, and the tools made from the method. A sheet metal blank has a predetermined design of etching resistant material applied to one surface to define exposed areas separated by resist areas. A layer of etching resistant material is also applied to a second surface of the metal blank which overlies at least the exposed areas on the first surface of the metal blank. The exposed areas on the first surface are then subjected to etchant applied from the first surface of the metal blank through the exposed areas to form a tooth shape with a cutting edge. The formed cutting edge terminates in a sharpened surface in the second surface, protected by the layer of the etching resistant material on the second surface of the metal blank.

Abstract: A method is shown for manufacturing a sheet metal tool from a metal blank in which a predetermined pattern of etching resistant material is applied to the back surface of the metal blank to define exposed areas separated by resist areas. A layer of etching resistant material is also applied to the front surface of the metal blank which overlies at least the exposed areas on the back surface of the metal blank. The exposed areas on the back surface are then subjected to etching treatment through the exposed areas to form a tooth shape with a cutting edge. The etching treatment is applied solely from the back surface of the metal blank, whereby the cutting edge is so formed terminate in sharpened surfaces in the plane of the front surface, protected by the layer of the etching resistant material on the front surface of the metal blank.