IRWIN marples wood drilling Forstner bits are constructed of tough carbon steel to stay sharp and produce precise pocket holes and flat-bottomed (Blind) holes. The ultra-sharp cutting teeth feature optimized angles to cut through hard and soft woods in significantly less time than traditional Forstner bits. With a reduced shank, they fit 3/8 and larger drills and drill presses. These wood drill bits are ideal for fine woodworking, cabinet-making and more.