I was out of the shop for a week on a work trip to Germany, then I had a bunch of home stuff to do so not much progress in the last couple of weeks. When I did get back in the shop I did some final prep work on the wing spars and ribs in preparation for riveting the upper skins.

At Oshkosh this summer I bought Avery’s 12″ double-offset back rivet set and mushroom back-riveting bucking bar. I had great hopes of back-riveting all the upper skin rivets, so Ellen and I started using this method to rivet the upper inboard skins.

Inboard skins backriveted

I must say that I was disappointed with the results. First, it’s not easy to get that long double-offset set squarely on the rivet and rib flange so we had some “drillers”, as Captain John would say, or poor rivets that need to be drilled out. And once we got the positioning right, it was obvious that the combination of back-riveting and Vans’ rivet length callouts were giving shop heads that barely met specs. Using longer rivets just magnified the problems of getting the set positioned correctly.

After getting a sanity check from Captain John on my riveting results, I decided to abandon the back-rivet set. With the tungsten bucking bar and a little practice with the straight mushroom set on my 2X gun, we were able to get results just about as good as back-riveting by using the normal shoot-from-the-outside approach.