Features: Can be applied to iron, steel, copper, aluminum and so on. Each bit has two ends to grind at a standard 60 degree angle. Sharp and durable, precise positioning and cutting edge clear Fast cutting speed and good chip removal for metal accurate center drills When rotating between chips, the two ends of the workpiece receive a corresponding centering bore. Prep tool for maintaining precise hole position Specifications: Quantity: 4 PCS Product Specifications: 1.0mm, 2.0mm, 2.5mm, 5.0mm Specific Dimensions: As 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: Center and Spotting Drills are traditionally designed to prevent the center of the lathe twist drill, twist drill from walking to create a starting point of the standard. 2. Used for workpieces that require center machining and center productionwithin the components. Package included: 4 x Center Drill Bits