Removing A Spinning Jawbone Thru-bolt?

[Marvwee]

If you've not managed to remove it yet, try running it under warm/hot water. Then use a rubbery non-slip mat to hold one end while carefully unscrewing the other end. It worked for me.
I had this problem a long time and decided to revisit it with the hot water tip.

 

[dr.chop]

if you haven't removed it try 1 of 2 things. First, less damaging to the surface of the head of the bolt is to use a rubber (silicone is best) pad of some sort and hold hard against the face of the bolt to stop it from spinning and unscrew from behind as usual. If that doesn't work, get a small piece of sandpaper (320 grit is good) and repeat that attempt. Works for me 100% of the time when they aren't stripped. If the threads are stripped, grab a small drill and drill out from behind.

 

[dr.chop]

manage to get it out and it's not stripped (usually it's the jaw), and if the face of the bolt gets roughed up, use some varying levels of sandpaper to smooth it back out. then you can dab some paint on it or whatever and be all fixed up.