Magnetic disk device and head stack assembly

摘要

Embodiments of the present invention relate disk drives, and in particular to realizing a positioning accuracy equal to that of an actuator having the mountable maximum number of suspensions, in an actuator having the smaller number of suspensions than the mountable maximum number. An embodiment of a magnetic disk device includes an actuator having an arm to which a suspension for applying a predetermined load onto a slider with a magnetic head is attached, and an arm to which a plate is attached instead of having the suspension. The plate attached to the arm in place of the suspension has a partially small section with respect to a section perpendicular to an arm longitudinal direction (constricted part), and the constricted part is located between a plate leading end and an arm attachment part.