We started today’s session with hole deburring and edge work on the four Wing Box J-Channels for the Right Main Spar. They are labeled and will now be set aside with the one’s from the Left Main Spar to be used on Section 20-Bottom Wing Skins.
Next, we final-drilled the remaining #40 holes in the Right Main Spar Upper and Lower Flanges and the tip and root of the web. Moving on to countersinking. To start, we countersunk the nutplate attach holes “just deep enough to fit the head of an AN426AD3 rivet”.
Here is the Upper Flange on the Right Main Spar with all the nutplate attach holes countersunk.
Here is the Lower Flange on the Right Main Spar with all the nutplate attach holes countersunk.
The three nutplates on the Right Main Spar web root.....
And the four nutplates on the Right Main Spar web tip.
I was under the impression (wrong impression as it turns out) that all the countersinking was complete.....IT WAS NOT! All of the remaining #40 holes in the Left and Right Main Spars have to be countersunk to accept a dimpled skin. So, countersinking continues. In order to get the correct countersink depth, I used a piece of scrap material (same thickness as the Wing Skins) and dimpled a guide. I purposely countersunk the hole to shallow and used the guage I made to slowly creep up on the correct depth.
Here is the completed Right Main Spar Lower Flange with ALL the holes countersunk. (The only exception is the center holes of the nutplates. There is a process outlined in the plans I will use to make those countersinks).
This is the completed Right Main Spar Upper Flange with ALL the holes countersunk. (The only exception is the center holes of the nutplates. I will use the same procedure in the plans to make these countersinks).
