This paper presents the application of zero velocity detectors in the field of indoor positioning for industrial tightening tools particularly in tandem with an extended Kalman filter to achieve reliable estimates in position. Inertial measurement units are promising devices to use in positioning systems. Data has been collected from IMU while moving in a predefined trajectory on a tightening test rig and post-processed in MATLAB using the implemented algorithms and the results are presented. They indicate that the error accumulation can be effectively controlled to 25 cm/min for the commercial grade IMU and 15 cm/min for the navigation grade IMU.