A Woodruff cutter, named after its inventor William Woodruff, is a specialized cutting tool used in machining applications to create Woodruff keyways. Woodruff keyways are semi-circular slots cut into shafts to accommodate Woodruff keys, which are small, half-moon shaped keys used for securing gears, pulleys, and other rotating components to shafts. The Woodruff cutter is designed with a unique curved profile that matches the shape of the Woodruff keyway, allowing it to create precise and accurate slots with minimal effort. Typically made from high-speed steel (HSS) or carbide, Woodruff cutters come in various sizes to accommodate different keyway dimensions and shaft diameters. They are commonly used in machine shops, automotive repair facilities, and manufacturing plants for producing keyways in shafts ranging from small motors to large industrial machinery.