Pounded 12 Rivets Tonight

OK, so I squeezed instead  of pounded them. Whatever method it takes to set them successfully matters not. These were the rivets to attach each of the two flange extensions to rear rib flange - 6 per side.

I tried to do all the right things - drill some practice holes, select the proper length rivet, study the best clamping/securing/riveting method, including positioning of the pneumatic squeezer for each rivet, cleco positioning, and a hole host of other things. I had t check the operation of my squeezer since I had not used it for a very long time. It seemed to function just fine.

I cut a small piece of .032 aluminum and already had another piece available to use for testing. The total thickness of the parts is .064, which is the same for the flanges and the rib. An AN470AD4-4 dome headed rivet appeared to the the correct size and length according to my rivet gauge. I match drilled 3 holes and then started out with my manual rivet squeezer just to check the depth settings on the rivet before mashed them with the pneumatic riveter. They appeared to be set properly:

Here is the riveter with the cup set on top and the flat set on the adjuster on the bottom.

Now for the challenging part. First, these parts are small, and there are a lot of rivets spaced very close together. At least 5-6 rivets were required in accordance with AC 43.13 procedures. This makes clecoing and riveting a bit of a challenge, because clecos are much wider than a rivet  hole, and it  makes it much more difficult to position the squeezer. You have to get creative about clamping the work and clecoing the parts on both sides. Here was my setup:

And this next shot gives you an idea of the positioning of the squeezer, which had to be changed from hole to hole, and then again when the part was flipped over to attach the flange on the other side.

It turns out that I should have applied some reverse clamping and support. The rivet sets were positioned so that I could apply some force against the smaller part and the manufactured dome head of the rivet to ensure that the parts would not separate from each other.The problem is that while pulling against the manufactured head of the rivet, the rib was allowed to bend just a bit, and this may have contributed to some less than perfect shop heads for some of the rivets. I did my best to flatten some of them out afterward, but I think they are good enough for this particular application. Here are the results:

Wow! Two years just to make a W408 rear rib flange look like the W709 rib that it is replacing. Now that this is done, the next step is to reassemble and reattach the entire LE to the wing yet again. Now that the flanges are attached to the rib, I need to drill two more holes, one in each flange, by match drilling the new holes from the existing holes in the rear of the wing spar. Once this is done I can finally start working on cutting the subskin to size and prepping the other ribs.

One small step for me, one less step to do..... and so it goes. (Astronaut humor).

KPR.