While attempting to hold the outboard flap rib in position and match drill through the pre-drilled skin holes the rib slid out of position by about 2mm resulting in the hole shown in Image 1.
Fabricated a new rib and this time instead of clamping and holding it in place I aligned the front flange centerline through the skin holes and marked the hole location through the hole with a fine Sharpie. Removed the rib, center punched in the center of the dot, drilled to 3/32" then re-inserted and clecoed to the skin. Repeted this on the remainder of the ribs with excellent results. Much easier to control hole location with confidence using this method.
