Features: Can be applicable to iron, steel, copper, aluminum and other processing. Each bit has a double end and grinding at a standard 60 degree Angle. Sharp and durable, accurate positioning, cutting edge clear. Quick cutting speed, and good chip removal. For precise center drilling in metals. When rotating between the tips, the two end faces of the workpiece receive the corresponding centering bore. Preparation tool to maintain the exact drilling position. Specifications: Quantity: 4 PCS Product specification: 1.0mm, 2.0mm, 2.5mm, 5.0mm Specific dimensions: as the picture Weight: 50g No. Body diameter Drill tip diameter Total Length #1 4mm 1mm 36mm #2 5mm 2mm 41mm #3 6mm 2.5mm 45mm #4 12mm 5mm 61mm Usage: 1. Center and spotting drills are traditionally used to make a conical hole for a lathe center in order to make a starting point for a standard twist drill, designed to prevent the twist drill from walking. 2. Used for work pieces with require machining between centers or producing center in components. Package Included: 4 x Center Drill Bits