This spade bit has a 1/4-inch hex shank system and it is best for use with portable power drills. The Self-Cut Speed Spade Bit performs extremely fast hole drilling. Its self-feeding threaded tip enables the drill bit to effortlessly pull itself into the wood for high-speed drilling with little exertion. Fast chip removal for rapid results is made possible by the specially shaped spade. In product tests, this drill bit produces holes 10 times faster than a standard spade bit. It is suitable for use on soft and hard wood, light building materials and plasterboard. 6-piece Self Cut Speed spade bit set in a roll-up case • Extremely Fast Holes • Self-Cut Speed Spade Bit performs extremely fast hole drilling • Self-feeding threaded tip provides high-speed drilling with little exertion • Fast chip removal and rapid results are made possible by a specially shaped spade • In product tests, this drill bit produces holes 10 times faster than a standard spade bit Specifications Diameter mm: 14,0; 16,0; 18,0; 20,0; 22,0; 24,0 Materials: Wood Materials in Detail: Hard/solid wood Softwood