Hi, I have a Jorgensen 10 inch woodworking vise and I need to know how to get the threads to engage to allow me to open and close it. It has a cast metal housing and in the bottom half are some bronze threads. I have cleaned it well but the threads on the vise don't make firm contact with the bronze threads.Is there a way to tighten this area or ? If any one can help I'll be grateful as the vise is in perfect shape if I could just get it to work. It is really heavy and I am a paraplegic and unable to wrestle it around easily. Thanks