The pin APPEARS to be hollow only because that end of the pin was pressed by a machine. The pin is solid for sure, but at one end (and only at one end),
OK, gotcha.
the end that is showing in the pic, has a "lip" that is pressed by a machine press once it's inserted.
That's the end you'll need to work on. You may have to actually drill that hole deeper though before you tap & cut.
I'll PM you my cell # in case you want to discuss.