For end and cross grain work. Precise and giving the sharpest cleanest of holes, this set also includes a RotaStop 90mm extension. Containing 15, 20, 25, 30 and 35mm Forstners each with the unique RotaStop shank which prevents slippage in a drill chuck. Each cutting tip is diamond ground; the periphery of the hole is pre-cut before the main cutters commence work which prevents splintering. The main cutters are sectional to create smaller shavings which permits a higher drill feed speed and faster work. Running any cutters at the correct speed is very important, this set of forstners should be run at the following speeds: 15 - 20mm run at 2,000-3,000rpm, 25-35mm run at 1500 - 2,500rpm. Forstners have up to 60mm cut depth; fitted with the 90mm extension gives a maximum 180mm cutting depth. All bits have a 10mm shank. Supplied in solid wood beech case.