Serrated press fit (SP) drill bushings press into soft materials such as wood, plastic, and soft metal. They have a serrated top that prevents the bushing from rotating in the jig or fixture when exposed to axial force. Type SP drill bushings are permanently pressed into a drilling jig, so they are suitable for single-step drilling operations where the drill bushings will not need to be replaced. They install flush with the jig and don't have a head, so they can be placed closer together than headed bushings. Drill bushings are installed into a drilling jig to guide, support, and position a drill or other cutting tool during metalworking tasks. They keep the cutting tool from wandering or bending as it enters the workpiece, maximize chip clearance, and minimize the risk of marring the workpiece or the jig.