SummaryIn this paper, machinability of turned steel defined by monitoring of cutting forces, tool wear, surface quality and chip shape is presented. Experimental investigations were performed on untreated carbon steel C45E (hardness 45 HRc) and on surface induction hardened steel C45E (surface layer hardness 58 HRc). The analysis of machinability was performed under different cooling and lubrication conditions: conventional flooding, minimum quantity lubrication (MQL) and a hybrid machining method, i.e. high pressure jet assisted machining (HPJAM). The investigation was carried out for higher values of processing parameters. The results show the advantages of the advanced cooling and lubricating techniques, i.e. an increase in productivity and a reduction in production costs. The analysis of the results shows that the application of HPJAM gives superior machinability. Beside excellent chip breakability achieved in HPJAM, especially in hardened steel machining, significant improvement in tool life and reduction in cutting forces can be achieved.