HS-105 is often called 5% Co HSS (high-speed steel). It has some of the increased red-hardness properties of M42 and is not quite as susceptible to shock. It is often used for making tool bits. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on wear resistance as well as forming, heat treating, and machining. Filing Code: TS-636. Producer or source: Timken Latrobe Steel.