So, what exactly does thread galling look like?

I use anti-seize on threads as appropriate.

What happens if you don't? What does a galled thread look like? Is it simply a worn and seized threaded union?

What does galling look like?

 

Sometimes it actually pulls the threads off the bolt, other times it just rounds the threads off. Most of the time the bolt will twist in half before the nut gives.

Low grade Stainless fasteners are really bad about galling.

 

Well, i could be wrong(wouldn't be the first time), but a few time's i've run into stainless nut's and bolts that have been used without anti-sieze. When they come apart, if they do, the threads are kinda stripped.
Basically smooshed, the sharpness of the thread is gone.
A lot of time the bolts break off before the even come loose..

Rat.....