Abstract : Applying cutting fluid is a common case in machining, as it can prolong the tool life. However, excessive using it may cause a bad affect on the operator and environment. Alternatively, applying minimum quantity lubrication (MQL) to reduce the bad effects yet gain a maximum advance of using cutting fluid. This study aims to determine the most optimal parameters in the AISI 4340 steel turning process with a minimum quantity lubrication method to produce the best chips formation. The best chips we