Several prototypes of an active boring bar for industrial applications have been produced for the reduction of cumbersome vibration problems in metal cutting processes. The active boring bar is used in lathe application to machine deep and precise holes in workpieces where long and slender boring bars are required. A vibration sensor embedded in the boring bar together with an embedded actuator is utilized in order to enable active feedback control. This paper discusses different techniques of measuring boring bar vibrations and their influence on the feedback control scheme as well as on the active control performance. Also the dynamic properties of the boring bar are considered when utilizing the different sensor techniques. The sensors that have been used are; accelerometer, strain gauges and piezo film.