5/8" HSS Ball Nose End Mill 4 Flute 1/2" Reduced Shank CNC Milling Cutter Used 5/8" HSS Ball Nose End Mill – 4 Flute – 1/2" Reduced Shank High-speed steel (HSS) ball nose end mill for CNC and manual milling applications. Ball nose profile is ideal for contouring, profiling, radius cuts, and 3D machining.