General description 15Pcs HSS Counterbore End Mill set is designed for use with milling machines and high-speed carving machines. These tools are capable of cutting various materials including copper, aluminum, tool steel, and cast iron. They offer high toughness and abrasion resistance, making them suitable for high-speed cutting of hard materials. The set reduces the number of tool changes required, improving the efficiency of machine operation and saving time in mold making. Technical specifications M3: Blade diameter: 5.9 mm, Start: 3.2 mm, Shank diameter: 6 mm, Total length: 45 mm M4: Blade diameter: 7.4 mm, Start: 4.2 mm, Shank diameter: 6 mm, Total length: 48 mm M5: Blade diameter: 9.5 mm, Start: 5.2 mm, Shank diameter: 6 mm, Total length: 51 mm M6: Blade diameter: 11.0 mm, Start: 6.2 mm, Shank diameter: 8 mm, Total length: 58 mm M8: Blade diameter: 14.0 mm, Start: 8.2 mm, Handle diameter: 12 mm, Total length: 67 mm Material: Steel Color: Silver Usage These end mills are