＊When D<3, the Helix Angle will be 37°. When D≥3,the Helix Angle will be 35° or 37°. ＊Special flute geometry and multiple helix angles eliminate vibrations. ＊Special Y-coating reduces wear and provides superior heat resistance. ＊Designed for mild steels, stainless steels, cast iron, tool steels, titanium alloys, prehardened steels and low hardness materials under HRC40.