IRWIN TOOLS 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 edges feature optimized angles to cut more quickly and accurately through hard and soft woods than traditional forstner bits. With a reduced shank, these bits fit 3/8 in and larger drills and drill presses. They are also ideal for fine woodworking, cabinet-making and more.