Y'all have hit the nail on the head. There ain't nuthin' that can be screwed on thight forever. I don't doubt that this fastener is the cat's meow, but from the looks of it and readin' the pictures, the metal material on the nut and the metal material on the bolt do not fuse at the molecular level, and that means weat and separation at the boundary (ah! those darn boundary conditions I studied all those many years ago).
Probably last forever and two lifetimes, but something will shake it loose.
Just my two cents.
