In this VAF thread and in the "27 Years of the RVator" I found an ingenious little tool for straightening rib flanges. The anvil is undercut by 11 degrees, so that when the aluminum springs back it's at a perfect 90 degree angle. I made both the anvil and the handle from some ash I had lying around from a 4x5 view camera I built several years ago.
Building this tool took me less time than I spent straightening the flanges in the empennage, and it makes the straightening job a breeze. Much more accurate, too.
