What is "surform"

a. A kind of tool that cuts by means of perforated steel holes with sharp rims n. A tool with which one grates, rasps, planes, or shaves material, especially wood, to form its surface.

A surform tool (also surface-forming tool) features perforated sheet metal and resembles a food grater. A surform tool consists of a steel strip with holes punched out and the rim of each hole sharpened to form a cutting edge. The strip is mounted in a carriage or handle. Surform tools were called "cheese graters" decades before they entered the market as kitchen utensils used to grate cheese. Surform planes have been described as a cross between a rasp and a plane.

Although similar to many food graters made of perforated sheet metal, surforms differ in having sharpened rims. Also, a surform typically is used to shape material, rather than grate it.