method for controlling installation of a head stack assembly in a disc drive . the head stack assembly is aligned in a head stack installation tool . a base deck assembly is advanced to the head stack installation tool , the base deck assembly having a post supporting a tolerance ring . a robotic assembly is dispatched to pick and press the head stack assembly onto the tolerance ring and post while mechanical resistance and distance traveled parameters by the head stack assembly are measured . the installation is aborted or completed in relation to the mechanical resistance encountered and the distance traveled , thus allowing use of minimum and maximum force thresholds with respect to insertion distance and assuring correct installation of the head stack assembly .