So, I went to install my new exhast studs yesterday. Coated them with anti-sieze, screwed them in as fas as I could with my fingers, then planned to simply double nut them to install them the rest of the way. I know it has been while (like a decade) since I have done this, but not exactly a lot to it right? Then why cant I keep both nuts from turning?

Put on a nut. Check.
Put on another nut. Check.
Tighten them together. Check.
REALLY tighten them together. Check.
seat the exhaust stud. notsomuch....

what am I doing wrong?

Uh, this is gonna sound silly, but take two wrenches and turn the nuts against each other. Top one spun toward the bottom one and vise versa. They need tension to bite the stud.

edit: Oh, and you must have bought decent hardware. The low grade crap will work without turning them against each other due to the rough threads.

Your not holding you mouth correctly. Ya got to get it really screwed up like this . They are not tight enough together. Use a lock washer between or triple nut it. You are working from the top one, right?

And if you have anti-seize under , between the nuts , remove it , you don't need a lubricant in the double nut operation . Installing the exhaust , those nuts could use some anti-seize , copper based if you got it.You are basically jamming one nut down on top of the other creating a bolt head to work with.
Good luck .......

Jack

As previously stated use 2 wrenches and turn the nuts against each other. Will have no problems after that.

Zach

gotta "really" mean it!
a lock washer or triple nuts,

Lock washer first, this is not common Scott.
Engine too clean?

lock em together drive in with top nut. sounds like you may need a retap.

when you figure it out
Bottom out the stud then back it off 1.5 turns, I think