I found it easier,, instead of grinding swedge/drum and getting mediocre results,, I drill/grind the heads of the stud, and pop it out the front, this doesn't damage the hole....
As stated above,, pound them out without removing swedge,, and you'll be looking to weld the new studs in,, or if they fit and hold enuff to tighten,, think ahead,, at the side of the road, trying to change a flat tire,, ONLY TO HAVE THE STUD SPIN IN THE HOLE... WHATCHA GONNA DO NOW..???