Hole saws made of HSS bi-metal with variable toothing. The variable tooth pitch (4 - 6 teeth per inch) guarantees chatter-free drilling. Hole saws with mounting thread, additional driver holes from 32 mm Ø. For efficient drilling of steel, cast iron, stainless steel, copper, non-ferrous metals, hard and soft wood, plasterboard and other materials. Saw length 50 mm, max. drilling depth 40 mm, mounting thread M 16. For mounting shafts (item no. 20 7580 and 20 7588). With a Ø of 89 mm