So far I've done one control surface on my plane and it seems to be working well. I'm using a little hand drill like a pencil that really works well along with the Robart hole tool. This lines it up fairly well. Then I'm using a dremel with a grind stone that just happens to almost exactly follow the contour of the hinge to enlarge the holes. I'm using a razor saw to cut the inlet on the control surface. One thing I'm concerned with is that the grind stone is polishing the holes more than it should. I might use another tool to put some kinda groove in the hole in the smooth area? Up to this point I'm really pleased at how it's all going together. Much harder to do than CA hinges but the rotation seems really smooth with no binding. I can tell it's going to be sweet!