Drove the Rivets for the cover plate

In case I have not mentioned this previously, lets just say that I am so glad that do NOT have put up with any of this stuff for the right wing fuel tank assembly. I finally got wipe to cobwebs off of my rivet gun and used it to set the 4 rivets to secure the cover plate over the hole. Since it had been so long since I had used the rivet gun and bucking bar to set rivets, I at least did the "smart" thing and took one of my test pieces that was already drilled, deburred, and dimpled, and still have a few holes available for some test rivets.

Another thing I wanted to do was test a flexible shaft flat rivet set with the rubber cup that surrounds the flat rivet set, which s at least 1.4 inch larger in circumference than my 1 inch flat set that have been using for my build up to this point. I bought this thing because it had the red rubber cup around the edges of the metal flat set, to allow it to grab the aluminum and keep it from slipping.SO I put it in my rivet gun, and well, lets just say that its a good thing I did some tests first, before I did the real thing.

Its hard to see in the next pic, but I was less than pleased with the rubber rivet set. The main reason was that the rubber extends almost 1/16th of an inch beyond the metal rivet set surface, and this does not allow the rivet set to sit directly on the rivet head before you squeeze the trigger on the rivet gun. The result was similar to what many others have experienced with this "stock" tool. The head of the rivet does not sit flush in the dimple and allows the head to rise up, resulting in a proud and improperly set rivet.

None of the pics of the shop heads came out very well, so you'll just have to trust me when I tell you that, in addition to poorly set manufactured heads, I also discovered that my air pressure was set way to high for the rivet gun. I don't even remember the last set if rivets that I drove with the rivet gun, but they must have been AN7470AD4 rivets, because the gun pressure was turned way up. The result on my test rivets was that the shop heads were all way over driven, and the gun was barely controllable.

Once I figured out how to turn down my gun pressure again, AND I switched back to my 1 inch wide flat rivet set, I was able to get satisfactory rivets.Here is the pic showing that horribly large flat set the rubber cup, and the bucking bars, rivet gauge, and my "normal" flat set already installed on the gun. You can see how much the rubber extends beyond the actual metal part of the larger flat set.

I think I can still make this larger set work, because I do continue to have problems with the flat set sliding off the rivet. I am going to have to sand or cut off the "excess" amount of rubber so that the flat set will make better contact with the surface of the rivet. I have to try taking off a little bit of rubber at a time, and run some more tests.

Now for the fun part. As I have mentioned many times before, the key to setting good rivets is all about how well you clamp the work piece to ensure that it will not bounce, bend, or vibrate in such a way that the rivet will not end up being set correctly. If you work alone and do not have a bucking buddy to help you, you absolutely MUST keep the work secure, since one hand will be operating the rivet gun, and the other will be working the bucking bar, the work piece has to be clamped down good. SO here is the contraption that I dreamed up - all for 4 rivets on one lousy fuel tank rib:

This "contraption" is made up of 6 different clamps, and 3 different wood blocks, all strategically placed on the work bench, with the rib positioned upright on the edge of the bench, with the bottom rib flange clamped in place first, followed by all the other clamps to make this assembly as rigid as possible, so I could set the 4 cover plate rivets. Here are the remaining detailed photos, showing exactly where and how I had to set each clamp to achieve the objective:

The smaller block of wood ha to  used to ensure that the hing for the trap door could be cleared. the other clamps had to be placed carefully so that the stiffening rings would not be compromised. Every single one of these clamps was needed until I felt that the rib was stationary enough to be ready to set these rivets. Let's just say that I am glad that this is the only rib that I have to do all this work on.

And the final result, after using my standard rivet set with a piece of masking tape over the face of the set, and my "fat man" tungsten bucking bar.

At the end of it all I was pleased with the results, and my rivet gauge confirmed that the rivets were set correctly. There will be a million more of these rivets to set if and when I finally get to the point where I am riveting the skins to the wings.

With this little "project" done, I think I will turn my attention back on the Leading edge assembly, and I will remark the lines for the rivets, cut line, and nut plate locations on the LE skin, using the edge of the skin as my reference point, so that my spacing of everything from one side of the bay to the other is accurate and consistent.

I am now very close to making that dreaded cut in my LE skin.

On another note, we had our first YE rally of 2018 yesterday - flew 2 kids and one adult - had some engine issues on the third flight adn had to RTB shortly after Takeoff. Getting tired of dealing with fouled plugs on airplanes so I may renting a different one for next month's rally.

We also had our EAA Chapter 301 Founders Day Brunch and Awards Ceremony. A great time was had by all at the Mount Vernon Country Club high on top of Lookout Mountain. The Chapter is 50 years old as of the 23rd of this month, which is a pretty significant accomplishment, and we received a very nice new Chapter Banner from EAA HQ that looks really sharp.

Till next time, KPR....