Abstract: Apparatus and method for balancing and limiting deflection of a disc of a disc drive. A disc stack comprises a spindle motor hub rotatable about a central axis, a disc mounted to the spindle motor hub, and a circumferentially extending peripheral disc ring affixed to an outermost peripheral surface of the disc. Imbalance of the disc stack is measured, and portions of the peripheral disc ring are removed in relation to the measured imbalance of the disc stack to nominally balance the disc stack. The disc ring protects the disc drive by cushioning contact between the disc and a rigid actuator arm supporting a head adjacent the disc.

Abstract: An improved actuator assembly for a disc drive, the actuator assembly having an E-block which at a proximal end supports an array of read/write heads in reading and writing data relationship to a plurality of spinning data discs which create air currents that convectively cool the E-block, the E-block supporting at a distal end an electrical coil which interacts with a magnet assembly of the disc drive to selectively position the actuator assembly in response to control voltages introduced to the electrical coil. A portion of the control voltage is dissipated as heat energy by the electrical coil, and a heat transfer plate is provided to thermally connect the electrical coil and the E-block to provide conductive heat transfer of the heat energy to the E-block which acts as a heat sink for the electrical coil.