I'm going to service and align this machine myself. I'm sure it will take me quite a while, and many times of practice, but I need to know how to do it. Can anyone tell me where I can find a spring scale for measuring the pinch roller tension? Any old hardware store will do? Also, I notice that the reel hubs are slightly off center. In other words, with the reels on, they don't spin exactly perfect. Is there a way to adjust this, or does this matter?