In another thread I saw a post about a Fender bass coming in from the factory with a big bow in the neck and the nut on the truss rod was bottomed out. I suppose this means that the threaded end of the truss rod is turned into the nut all the way and there isn't any more ajustment. How can you tell if the truss nut is bottomed out? To say, "It won't turn anymore", doesn't really answer my question. If a truss rod won't turn, it might be screwed all the way in or it just might be stiff. The amount of force necessary to find out could break it. How do one know?