These Roman Carbide Forstner Bits are some of the nicest Forstner bits available! Micro-grain carbide cross tips and center cutters stay sharper longer for years of dependable service when drilling hard and soft woods, face grain, end grain and figured grain. Carbide cross tips and center cutters also provide smoother, chatter-free and faster cutting results. unlike round shanks, which result in scarring and diminished accuracy. Hex shanks fit 3/8" drill chucks.