I was always told that if I wanted my fabric to be cut straight then I should clip and tear. Is this the way you make your edges straight so that they will just pin right in the frame for quilting? I ran into this problem when I cut my backing and was going to load it on the long arm frame. It sagged on the sides. I soon discovered it was because my sides weren't all cut straight. How do you make sure you backing is straight to load properly?