Disk drive with self sealing screw attachment of actuator pivot

A disk drive enclosure includes a cover and a base having a first hole therethrough. A head actuator is pivotably attached to the base by an actuator pivot bearing having a pivot bearing shaft with a lower internally threaded section and a flat annular support surface that is facing and in preloaded contact with a flat mating surface of the disk drive base around the first hole. A bearing member is disposed around the pivot bearing shaft and between the pivot bearing shaft and the bore of the actuator. A first screw has an externally threaded section that is engaged with the lower internally threaded section of the pivot bearing shaft. The first screw has a screw head with an external annular seating surface in contact with and forming a continuous annular seal with an internal annular seating surface of the first hole.