Forstner Bit with Quick Changer, 8-Pieces Size: 1/4", 3/8", 1/2", 5/8", 3/4", 7/8" and 1". 1-piece quick change Quality, precision ground, steel bits in 8-piece set Designed to drill flat bottom or through holes cleanly in end grain Easily enlarge existing holes and can bore any arc of a circle Great for mounting mini-quartz clock movements, cup hinges, and door locks