A return spring assembly for returning a handle to the horizontal orientation includes a spring housing having an outer flange that contacts an outer surface of a door around the perimeter of a bored opening and an inner portion with a curved section that securely supports a latchbolt lock mechanism when an identical return spring assembly is installed on an opposite side of the door. A spring is driven by two spring drivers operating with a lost motion connection to the handle spindle to alternately compress the spring from opposite directions as the handle is rotated in opposite directions. The spring is positioned to not interfere with a linkage extending out from the latchbolt lock mechanism.