I wouldn't use a hammer to install the new stud. Two options

1. Press

2. (some debate on this) after inserting the stud from the back of the hub place a washer on the stud and put on a lug nut (reversed so the flat side of the nut faces the hub) and draw the stud into the hub. Use lubricant on the splined parts of the stud.

You shouldn't need to swedge the new stud. If the hub hole wasn't damaged and the stud is tight the lug nut will keep it iin place.

Good luck
Frank