Hole saws made of HSS bi-metal with Vario toothing . The variable tooth pitch (4 - 6 teeth per inch) guarantees chatter-free drilling. Hole saws with mounting thread, from 32 mm diameter additional driver holes. For efficient drilling of steel, cast iron, stainless steel, copper, non-ferrous metals, hard and soft wood, sheetrock and other materials. Saw length 50 mm, max. drilling depth 40 mm, mounting thread M 16. for mounting shafts (Order No. 20 7584, 20 7586 and 20 7589). for mounting shafts (Order No. 20 7584, 20 7586 and 20 7589). Diameter 67 mm .