the thread looks rather modern (is it metric? I think it is possible to identify this way.
https://www.adaptall.com/info-tutori...ic-threads.php)
I think , as far as dor knobs would be, rather slippery a shape, which probably defeats the purpose.
If this belonged to a weapon it must be a modern contraption and may be fitting a war axe ( topo) or hammer, more that it would be a sword pommel (methinks).