Double nut it if you have enough thread, or get longer studs so you can. Make sure the studs are ran in snug cause if they vibrate out just a little then the nuts are lose and vibrate off. Put new flat and lock washers on it, and check it every couple of days to make sure it's snug. These motors (some more than others) love attention. Don't get carried away when running the studs in or you will blow out the casting.