I run a Tap into the RamRod tip hole. Tap it for whatever size & thread happens to fit,,and it doesn't have to be
any sort of perfect fit either. A sloppy loose thread is fine.
Then run the die of the same thread down over the ram rod end far enough to bury itself in the tip when the two are screwed together.
Sometimes this takes a couple of passes and trys so the threads you cut on the RR don't show (cut too far).
You usually don't have to shave the ramrod dia down any, the die will do that for you if you start it from it's normal 'Start From This Side'.
The metal cutting Dies & Taps will cut very nice threads in hard wood.
When things fit nicely,,put SuperGlue on the threads and QUICKLY screw the 2 together.
The SG will set up very quickly in the confined space. If you dawdle or hesitate in threading the two together you may find yourself with the tip only partially screwed into place and refusing to go any further.
You can use regular expoxy if you feel better about it, but it'll take whatever amt of hrs to set up.
Then drill, pin and rivit a pin into place very lightly a finish off the assembly no matter what you use.