I have a new Grizzly 490X jointer. It runs smoothly, quietly and all-in-all I am pleased. However, I am experiencing one source of irritation, whenever I move the fence the fence does not stay square with the table. I doesn't move much, but enough that I have to go through the process of re-squaring the fence to the table. As you can imagine, I have tightened everything that I know to tighten, but it still moves. Any thoughts?