A new concept of spindle head for heavy roughing operations has been developed integrating an inertial actuator and an accelerometers in a heavy duty spindle head. With this head is possible to introduce active damping using the inertial drive, and improve the dynamic stability of the machine. A novel mechatronic milling model is employed for designing the actuator, where the effect of cutting process and inertial actuators can be simulated. The validation tests of the new actuator are shown and all mechatronic system is completely integrated on the machine. Finally, experimental cutting tests are performed, showing that material removal rate is doubled with this new spindle head.