AUTOTOOLHOME 600 Nano carbide end mill tools excel at working carbon steels (~HB225), alloy steels (HB225~325), pre-hardened steels (up to HRC45), hardened Steels (HRC40~45), cast iron Carbide milling bits Diameter: 1/4'', Shank Diameter: 1/4'', Flute length: 3/4'', Overall Length: 2-1/2", 4 Flutes End Mill spiral router bit is used for side milling, end milling, finish machining, etc. Unequal flute spacing and irregular helix flutes ensures stable machining of difficult-to-cut materials and higher efficiency,Vibration absorption provides stability, high efficiency finishing and improved chip disposal This 1/4 inch Square Nose End Mills,highly optimized carbide material and coating pairing means superior wear and chipping resistance in your cutting applications