Tuning actuator arm displacement characteristics to reduce damage from mechanical shocks

An apparatus and associated method are described which change the mechanical response characteristics of an actuator arm in a disc drive such that damage to the disc drive resulting from mechanical shock is minimized. An actuator arm is provided which has a groove that extends along a side portion of the actuator arm. A side rail is attached to the side portion of the actuator arm, and is preferably T-shaped so that the side rail mates with the groove. The side rail can be constructed of a stiffening material and/or a damping material as desired to change the mechanical response characteristics of the actuator arm to reduce contact between the actuator arm and the disc surface which results from mechanical shock to the disc drive assembly. In the method of use, a groove is machined into a side portion of an actuator arm and then an actuator arm side rail is inserted into the groove.