1. Draw a center line between the center of the tooling holes. Measure down, 11/32” and draw a line parallel to the center line. Measure up ¾” and draw a third line parallel to the first two as shown below. Also mark where the skin stiffeners are located as shown.
2. Cut on the top and bottom lines drawn in step 2, between the 2 rear lightening holes.
3. Pre drill 4 #40 holes in each skin stiffener, same as for Rib 1. Position skin stiffeners on rib, and transfer drill #40 holes into rib. Updrill the 8 #40 holes to #30.
4. Position bellcrank brackets with a 3/4" spacer and an AN4-14A bolt between them. Transfer drill 8 #40 rivet holes into rib updrill to #30. Transfer drill 4 #30 holes for the bolts into rib and skin stiffeners, and updrill to 3/16". It is recommended to not permanently install brackets until after rib flanges have been drilled and optionally dimpled.
