Riveting the stiffeners to the skins^1.5h

I got my double offset back riveting set, so I continued riveting the stiffeners to the skins.

It turned out to be much harder to use. The normal back rivet set works perfect, 40 PSI (with some flow reduction on the gun itself, which I haven't changed so far), about 1 or 1.5 seconds, and it comes out perfect. Very consistent results.

The double offset set is a different story. First, it requires much more pressure. I used 60 PSI, and I have a suspicion that I need more, as a rivet seems to flatten sometimes instead of "swelling". Also, I get clinched rivets. I keep it as vertical as I can, with my helper spreading the skins apart to give me the space, and still sometimes rivets clinch to the side. I would say, about 20% of aft rivets came out not-so-okay.

One rivet I tried to replace multiple times until I had to install an "oops" rivet instead.

It looks okay on the skin side.

Here is an example of a slightly clinched rivet. Actually, both of the aft ones.

I replaced some clinched rivets but left others as they are. It seems I will cause more damage by trying to replace them.

This one on the left came out okay. The one on the right is over-driven, it measures about 0.036", which is slightly less than the acceptable 0.038". I am keeping it, though, as, again, I will cause more damage replacing it.

Overall, I am not extremely happy with the result I got for the aft rivets, but I will keep them. Again, I think, I will know better at the end of the project to decide what to do about these parts.