Bosch Hole Saws HSS-BiM One-piece Construction with Centre Drill - Bosch 2609255601, This Bosch HSS Bi-Metal holesaw combines the blade and centre drill as one part making it run with less vibration and more precision. Suitable for aluminium and other non-ferrous metals, iron and steel, acrylic, wood and plastic. Bosch 2609255601 Hole Saw HSS-BiM 20mm One-piece Construction with Centre Drill