A worm gear drive operator having immovable flat thrust bearing surfaces at each end of a worm gear drive for absorbing thrust forces and keeping direct mechanical rotational forces away from the cover plate and housing base during rotation of the worm gear drive. The worm gear drive operator assembly is capable of vertical adjustment of the actuator arm while providing thrust support. A threaded post about which rests a bearing for the actuator arm, and is secured in place by an adjustment screw received within a threaded post on the cover plate.