This investigation, vibration analysis of cutting tool in turning of 42CrMo4 alloy steel using CNMG120408SMRH13A insert. Tool vibration is the important phenomenon which affects the life of the cutting tool, machining quality and behaviour of the metal cutting process. In metal cutting, tool vibration is the significant factor affecting the surface quality of machined surfaces. In this experimental work, control this vibration should be arrested by external force. In the proposed system damper method has used to control the tool vibration. It will be predicted by comparing the parameters of cutting speed, feed, depth of cut, material removal rate and surface roughness of turning operation. The generated vibration is measured. The machining performance has derived by the analytical method and experimentally.