[brainanator]

Have you ever screwed a screw that had dried loctite on it? It makes it more sticky, kind of acts like a lock nut. I would try what KMN said. Let some loctite dry on the hex or the nut, or even with them screwed together. Get some loctite dried up on the threads and give it a shot. If it doesn't work, you're not out any money, if it does, great!