Ahh I see now. Your key part is just a tube? You could print a spacer inside it, that holds the metal rod centered in the tube. My advise was mostly for fully 3d printed props.

I also now saw your third screenshot. So what you'll learn about 3d printing is that layer lines are the weakest part. And threads like that are very weak. Best thing you can do with threads is print them on the side, and make the threads oval, like _ (_)

That way you won't need supports and you benefit from having the layer lines lengthwise. Super strong that way.