This paper presents a practical tuning method for high speed machine tools to improve the motion accuracies. Vibration in high speed feed drive systems is easy to be inspired by high response in the servo systems. In order to balance the servo and vibration errors, the CNC servo parameters are tuned and a couple of candidates are presented by using a simulation model identified in the experiments. As such off-line tuning can offer the good chance to explore many combinations of servo parameters, a few experimental tests is enough to decide the most adequate combination. A case study of an existing machining center shows that the proper tuning of servo parameters reduces the vibration in the machine tool and improves its motion accuracies.