Description: 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. Used for work pieces with require machining between centers or producing center in components. Quick cutting speed, and good chip removal. For precise center drilling in metals. 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. Preparation tool to maintain the exact drilling position. When rotating between the tips, the two end faces of the workpiece receive the corresponding centering bore. Specification: Material: high speed Steel Coating: Titanium Coating Degree: 60 Size Including: 1.0mm 1.5mm 2.0mm 2.5mm 3.5mm 5.0mm Total Length:33mm,36mm,40mm,43mm,49mm,60mm Package Includes:(2 Pack) 6Pcs/set HSS Center Drill Countersink Bit