Here are a few picks of my drill press capper project.
Found a piece of all thread in my scrap bin that matched the capping bell perfect. Got lucky there.
Chucked it up with some sandpaper to protect the treads and turned it down to about 3/8"
The end result. I put a taper on it for no particular reason. It just worked out that way.
This thing works really great! The only problem is now I have a drill press on the kitchen counter. But my wife doesn't seem to mind too much.