It is well known `act that manufacturing sector looks for two main traits—increased production and superior quality. In today’s competitive market environment, modern manufacturers are constantly searching for optimum processes and parameters that will manufacture machine components in cheaper methods but with an increase in the quality of the products, low wastage and reduced energy consumption. EN8 is an unalloyed medium carbon steel used in all general-purpose engineering applications requiring higher strength than mild steel. This study focuses on the investigation on how the cutting factors (cutting speed, feed rate and depth of cut) affect the productivity, i.e., rate of material removal and the quality of surface in case of EN8 steel. This is produced during the shaping operation of untreated and heat treated (hardening and tempering at 550, 600 and 650 °C) EN8 steel using HSS as the cutting tool material. Tempering heat treatment decreases the hardness of EN8 steel which would increase the machinability (high material removal rate and lower surface roughness) of the material. It can be inferred that the increase in the machinability would decrease the energy consumption rate during machining of the material. Taguchi L9 design of experiments consisting of 3 factors and 3 levels were employed for optimizing the rate of material removal from the surface and surface quality among the chosen levels using signal-to-noise ratio assessment. Analysis of variance was used to model the effect of machining factors on the output factors. Additionally, regression models were formulated to establish the relationship between the machining factors and output parameters. Heat treatment imparted better mechanical properties (toughness) to EN8 steel, exhibiting better machining characteristics which may be in turn related to reduce energy consumption during machining. The increase in tempering temperature caused the material to become tougher and better machinable.