11/16"? I assume thats a typo since it would be smaller than the element threads. Maybe 1-11/16"? I would be careful mounting an element in a hole that is too big. If the element gets torqued when the seal BARELY seals the outside of that hole, you could get a leak in a very invonvenient place. I have seen one setup where this happened, and the guy took a 1-1/4"-1" bushing (make sure that the element will screw into the bushing deep enough to seal at its seal), and used a silicone gasket and a 1-1/4" NPS nut to make a sort of bulkhead in the keggle, and the element screws into it with its original seal. Overcomplicated, yes, but he had no means of welding/soldering and it works like a charm.