This saw tooth forstner bit is made from high grade Carbon Steel & meticulously heat treated. They cut fast, with the grain or across it & can drill overlapping holes in any direction & are chosen for exacting & delicate work, such as scroll & scolloping operations. D 1 3/8 inches D 3.5cm C 57.15 mm OL 88.9 mm OL 3 1/2 inches Shank Dia 3/8 inch Shank Length 31.75 mm Recommended max. speed 575 rpm