A ban saw uses a blade consisting of a long, narrow, flexible band of toothed metal, and may be powered by wind, water, steam, electrical motor or animal power. The band rides on two wheels in the same vertical plane with a space between them. Band saws can be used for woodworking, metal working, or for cutting a variety of other materials, and are particularly useful for cutting irregular shapes. The radius of a curve that can be cut on a particular saw is determined by the width of the band.