The Study of Effect in Turning on AISI 4140 quenching water and oil by Engine Lathe 400x600 (Center lathe) BE-LA-11. cutting tool was carbide. the factors were consisted for study of effect in Surface Roughness , Characteristic of Chip , Cutting Force and Tool wear on AISI 4140 quenching water and oil is cutting speed in range of 80-150 m/min and feed rate in range of 0.12-0.22 mm/rev. The results revealed that temperature of cutting tool in turning AISI 4140 quenching by water are lower than quenching by oil and surface roughness was inclined to the same way, When cutting speed increased surface roughness decreased.