Last night I clecoed the Wing Walk Doublers and Inboard Top Skin to the Wing assembly. Today, the real work starts. To begin, I match drilled #40 the rivet holes for the nutplates that will be installed along the inboard edge of the Inboard Top Skin. As shown in the picture below, there are eight locations that various types of nutplates will be installed.
Next, all the #40 holes common to the top Inboard Wing Skin, Wing Walk-FWD, and Wing Walk-AFT were final-drilled. Now, the screw holes for the nutplates were final-drilled to #19. In the picture below, I circled two nutplate locations. The plans caution to make sure you drill one particular #19 hole in the right location . The nutplate on the right is a single leg nutplate and the #8 screw will eventually be installed on the far right of the three holes. The remaining seven nutplate locations, like the one circled on the left, will use regular nutplates and the #8 screw will be installed in the center hole. I will post a picture of the three different nutplates used in this location when they are installed.
On the bottom right in the picture below, is the AFT most nutplate attach hole. In this picture, the hole has already been dimpled for a #8 screw. Prior to dimpling, this hole also had to be final-drilled to #19. However, it does not have any material underneath the Skin. So, I put a piece wood under the Skin and drilled the hole into the wood. The plans caution that holes dimpled to accept #8 screws tend to crack if you are not cautious with the deburring. After dimpling, I can’t see any cracks.....guess I was cautious!
Moving on.....the next step is to countersink all of the holes common to the Inboard Top Skin and Wing Walk Doublers. The plans caution not to countersink the holes to deeply and state that a countersink that is .005” proud of the Skin is acceptable. Unfortunately, I have to stop work here for tonight because my gauge only goes to .012”. So, I’ll have to get a proper gauge and continue tomorrow.
