Surform

A surform tool, or surface-forming tool, is a rasp-like implement made from a strip of perforated sheet metal whose punched holes have sharpened rims, mounted in a carriage or handle shaped like a plane, a file or a rasp depending on the model. Described as a cross between a rasp and a plane, the surform was marketed under that name decades before similarly perforated graters entered kitchens as cheese graters, and it differs from an ordinary food grater mainly in having deliberately sharpened cutting rims rather than simple punched holes.