Machine counter sunk the skin to brace rivet holes. I chose this method because I could not find a description in the manual on what I should do. The flap hinge is riveted to the flap spar in the same mannor. I machined the brace over a length of wood so the counter sink would be held concentrically. After performing the counter sink I preped and alodined the braces. They are now ready to install on both wing.s
