I'd agree with Drewsy. It looks a lot like one by shape and the thread, but the holes around the top are odd. And there was no set-screw hole. I think every one I have dug, including the one with no threads, has that one hole so it stays in place.
You're right Jim, there is no set screw. I've never found an ox knob so I didn't know there was even a hole for the set screw. My guess now is maybe a handle to a wood burning stove.