Brief Description: Flaps - Drilling the Hinge - WARNING
WARNING: Use less than 1/4 edge margin on flap hinge so you'll have enough hinge flange when it comes time to drill hinge to wing (see 3/11 entries).
Then you clamp on the hinge for match drilling to the spar flange. I studied the drawing to make sure I had it oriented properly and aligned at each end properly. I left the pin in because plans say this helps keep it straight. I positioned it with little plastic clamps. But then I found my old Boeing pinch clamps and used them to hold the hinge in place for drilling.
But first I drew a red line down center of hinge tab so I would see it through the skin holes and drill it consistantly. The hinge tab is 1/2 inch wide so measurement for line was 1/4 inch to center. Then I clamped it and drilled it. I clecoed as I went and moved the clamps as I proceeded.
After finishing, one hinge moves up and down fine. But the other one binds a little as if it is bent or something. I examined it. It may have a slight bulge in it, but not much and bind is small. I removed a few clecoes and pushed the bulge out of the hinge and redrilled. This made a couple holes slightly oval but reduced the bind considerably. I'll use a presqueezed rivet here to fill in the enlarged hole.