Spacer key for attaching a head gimbal assembly (HGA) to a rigid actuator arm

A spacer key used for installation of first and second head gimbal assembly (HGAs) onto adjacent first and second actuator arms of an actuator assembly, each of the first and second HGAs having a base plate configured to abuttingly attach to a distal end of the associated first and second actuator arms, the spacer key comprising:

• a support arm having a base support surface and adjacent first and second support surfaces opposite the base support surface, the support arm having a first thickness from the first support surface to the base support surface and having a second thickness from the second support surface to the base support surface, wherein the second thickness is greater than the first thickness by a distance nominally equal to a thickness of a selected one of the base plates of the first and second HGAs so that the second support surface contactingly biases the first HGA against the first actuator arm while the base support surface contactingly biases the second actuator arm when the second HGA is not disposed between the first and second actuator arms, and so that the first support surface contactingly biases the first HGA against the first actuator arm while the base support surface contactingly biases the second HGA against the second actuator arm when the second HGA is disposed between the first and second actuator arms.