You may need to do more that grind the bottom side as I believe there is a chamfer that the ball stud expands into. I bleive the guidance is to drill a hole in the center that will allow the metal that is deformed into the chamfer to fold into the hole as you press the stud out.
It was PITA for me, even after the grinding and the drilling.
I don’t have a proper press, and the job was ALL that my loaner ball joint press wanted. I think it took a combination of vigorous beating plus the press.
