The present work concerned an experimental study of turning on 904L Stainless steel by a TNMG coated carbide insert tool. The primary objective of the ensuing study was to use the Vegetable oil Based cutting fluids in Machining process in order to determine the effect of machining parameters viz. cutting speed, feed, and depth of cut on the surface roughness, Material removal rate, power consumption, chip formation and tool life of the machined material. The objective was to investigate the machinability of hardened steel by using vegetable oil based cutting fluids. Castor oil and Soyabean oil are the two vegetable oil based Cutting fluids used in Experimentation. The experiment was conducted in an experiment matrix of 27 runs designed using a L27 Orthogonal Array of Taguchi Design of Experiment. Surface Roughness was measured using a Mitutoyo SJ-210 Surface tester and Power Consumption is found with Power Capacity Analyzer. The data was compiled into Minitab ® 16 for analysis. The relationship between the machining parameters and the response variables were analyzed using the Taguchi Method. Analysis of Variance (ANOVA) was used to investigate the significance of these parameters.