Today was kind of challenging as I installed the end rib in the leading edge and the flange that supports the tank when installed next to the leading edge.
You start by setting the end rib in place and making sure it is square with the end of the leading skin. (this turned out to make the rivet holes really close to the web on the leading edge. I wish I would have let the rib stick out just a bit so that the holes would be centered)
After the rib is in place you have to drill it from the bottom using the holes in the spar as a guide. Here I used a 12 inch bit and my right angle drill to make sure the rib was drilled straight. Worked well..
Once the bottom of the rib is clecod to the spar, you insert the flange between the rib and the skin and use the skin holes as a guide to drill the flange and the rib which don't come pre-drilled.
You have to make sure the rib stays flush with the outer edge of the skin and the flange stays straight per the measurements provided in the directions. This part is challenging because for some reason the whole assembly wants to keep moving on you. I got it done and was happy with my results, but I think this is one of those tasks that you can do better each time you end up doing it again. Like I said earlier I would have let the rib stick out about a 1/16th of an inch so that the holes would be more centered on the flange. In my case they ended up real close to the web, but I was still able to get my dimpler die in there, so I think we are OK.