Never really had a problem with that. The thing to do is to use the tool to push the screen into the frame first. Then put the rubber gasket over it. When you push it in first, if there's too much slack, you just adjust it and do it again. You cut the excess with a razor blade that you just run along the side of the rubber gasket.I attempted to re-screen some of my frames the year of the bad hail storm that tore 3 screens and broke a window. I could never get it the right "taughtness". It either had too much slack, or it was so tight it deformed the frame. I finally just had new ones made at a window shop and put the old ones in the attic.