Abstract The application of experimental modal analysis (EMA) was restricted to the verification of theoretical model previously. The purpose of the lumped model was to extend the application of EMA and reduce the number of DOFs of the original system while the dynamic characteristics were kept the same. Based on EMA, a lumped model of a vertical milling machine with 7 degrees of freedom (DOF) was created using the mass and spring-damper elements. This model was proved to be accurate after comparing the frequency response function (FRF) with the experiment results. Furthermore, the tool point FRF was synthesized and chatter stability was predicted. The relationship between chatter frequency and mode shape was revealed, which can be referenced for the future design of other machine tools.