I’ve found a good way to stretch insect screening tightly and evenly across wooden framing members for screened doors, windows and porches. First I place the empty frame on top of a pair of 2×2 supports. The supports in turn rest on a rigid platform. I use two C-clamps to bow the frame downward, and I staple the screen to the unbowed framing members on the ends. Once the clamps are removed, the frame provides its own tension, tightening the screen. Then I staple the screening to the side rails, and trim its edges with wooden moldings.
M. Felix Marti, Monroe, OR