A robotic tool for assembling a portion of a disk drive includes a movable end effector that includes a first portion and a second portion that is movable relative to the first portion. The first portion may be configured to engage the actuator assembly and the second portion may be configured to engage the flex circuit connector. A controller may be provided to control the movable end effector, causing the end effector to pick up the head stack assembly in a first configuration, move the second portion of the end effector relative to the first portion thereof so as to articulate the head stack assembly into a second configuration that is different than the first configuration, and place the head stack assembly into the base.