The machinability of powder metal (PM) steels depends on the microstructure of the steel. With increasing carbon levels and alloying the machinability of PM steels decreases. Heat treatment only increases the difficulty of machining. To improve machinability of PM steels, machining enhancers are often admixed with the steel powder. In previous studies, the SM3 additive has been shown to greatly improve the machinability of different PM steels while not negatively affecting mechanical properties or corrosion resistance. In this study, the SM3 additive is evaluated in both carburized and sinterhardened materials. The additive will be evaluated on both laboratory and production components. The results of the study show SM3 offers an opportunity to improve both tool life and productivity when machining hardened materials.