Setting the Final LE rivets, Cont'd.

One of the other things I failed to mention in previous posts is how important good lighting is when riveting these enclosed structures together. This was yet another reason why I wanted to have a portable, moveable work surface that I could position various ways to take advantage of the lighting as necessary. The problem that I encountered, regardless of how positioned the table and LE, was that I have very poor lighting in my garage to begin with. Even after I thought about positioning the table so that my 4 high intensity 150 watt work lights could focus all of their available light on the inside of the LE, I still did not have enough light in there. So what to do.....

Solution was to grab my trusty Ryobi adjustable flash light with a LO battery pack, and one of the bath towels, and lay it on its side with the head of the light poking through the aft lightening hole of a rib on either side of the rib flange whose rivets I was about to set. I placed the towel underneath it s that the vibration from the rivet gun would not cause other damage to the skin or ribs via the flashlight bouncing around. This allowed me to directly focus enough light into the bay while still allowing enough room for me to insert my hand and bucking bar of choice into the bay.

Here are a few pics showing that setup:

As I began working on these forward rivets, I tended to position myself in such a way that the rivet gun was centered directly over the rivet to be set, and then I would bend down to see the positioning of the bucking bar over the rivet shaft underneath the skin. I mostly watched the bucking bar while riveting, relying on the gun to stay in position with the proper amount of force applied. As I have previously reported, sometimes this worked as expected, and other times the gun would slide out of position and I would have to stop and reset everything all over again. I do not like not seeing the bucking bar because that usually leads to improperly set, overdriven, or canted shop heads. For some of these rivets doing it blind by not being able to see the bucking bar was unavoidable. These were mostly the most forward rivets where I had to pay much more attention to the gun position due to the extreme curvature of the LE skin. my biggest concern about this is having the bucking bar slide off of the rivet shank, which leads to all sort of potential damage - damage to the rivet, damage t the skin, or damage to the rib, or sometimes all three. I have seen it all during my short riveting career. So when I can't see the bucking bar and verify its position over the rivet shank it really bothers me.

The pic above showing the light shining against the rib flange and the rivet shank also gives yo an idea of the curvature of these surfaces that you have to deal with. Each rivet is at a slightly different angle than the other rivets, so to set these properly the bucking bar has to be placed t the correct angle for each one. To figure this out, I tend to use the tips of my fingers against the rib flange to gage the angle that I am dealing with, and then use my fingers t adjust the angle of the bucking bar to match what I am feeling. its not very precise, but its the best you can do on these hard to reach rivets f working by yourself. Of course the best solution is to have a riveting buddy, so that each of you can focus on the gun or the bucking bar and not worry so much about it. However, this causes other problems when working with small confined areas where more than one body may also cause its own interference problems that have to be worked out.

Here is another pic showing the positioning exercise of my fat man bucking bar against one of the rivet stems. For the rivets along the rib flanges this was not too difficult, but where I had rivets, nutplates, and additional skin-to-subskin rivets all very close to each other, I had t choose between different bucking bars for different rivets to maintain clearance from and prevent possible damage to the other obstructions.

In fact in the same pic to the left through the lightening hole you can get an idea of all the rivets and nutplate proximity to each other.

As I proceeded with setting the bottom rivets, I had to stop and slide the LE into different positions to allow clearance for the rivet gun. This required removing the long bar clamps holding the 1x4 against the rear rib flanges, sliding the next bay of the LE into position in the cradle, and re-clamping the rear brace back on again. I should also mention that a very important part of this whole assembly is the 1/8th inch thick weather proofing vinyl tape on the cradle supports. This is an absolute MUST for tis assembly, because without that bit of shock absorption between the wood and the outer LE skin, you would be causing pretty severe damage to the LE when you attempt to set each rivet. So I check this stuff every time I reposition the LE in the cradle to make certain that it  is properly placed.

Here are some shots taken from both sides after finishing the initial rivet setting exercise for the bottom side rivets. Most of them seem to set pretty well, but I did have issues with the curved surface of the forward, just as I had expected I would.