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dwollen89

Well Known Member
Ugh...I'm on the struggle bus lately. I'm riveting the leading edge skins on my left wing and I can't seem to shoot the rivets straight. They are clinching to one side too often. Not drastically, but I can't seem to get them straight. I can't figure out what's going on, as I typically don't have any issues bucking rivets.

I noticed that the rivets seem really loose in the holes. I final sized them with a #40 reamer and dimpled them with Cleaveland standard dimple dies on a C-frame. So there is no reason that anything should be out of spec. If I pre-squeeze the rivets, that helps tremendously in getting them bucked straight. I really don't want to have to pre-squeeze thousands of rivets, but I'm not sure what else to do.

I might order a #41 reamer and see if that helps. I also see that a few vendors offer an over sized AN426-3 rivet that's just slightly bigger. Has anyone else encountered this or have any thoughts?
 
Had the exact same problem last night on my leading edge skin top stiffeners. Ended up with a couple of oops rivets after botching the same rivets multiple times and had to open up the holes a bit.

I found that I needed to relax my bucking bar hand so the bar would tap slightly vs holding it with a death grip. My experience is rivets tend to smear over when you hold the bucking bar too tightly.

I've also found it helps to align my forearm with the gun and have a nice square grip on it. Helps to keep the forces parallel with the work.

I'm still learning also but hope this helps.
 
What kind of riveting gun and what pressure? How many hits to set the rivet? what kind of bucking bar?
I had trouble with a 2X gun (too light and high frequency hits), much better after I bought a 3X gun. I had the "standard" cast iron bucking bar set. Much better after I bought a tungsten bar. Now I have three different ones. My flush rivet set is absolutely flat. Some are convex which I never use.
 
I'm using a 3X gun from Planetools with a swivel mushroom set with the rubber ring. I honestly don't know the air pressure, because it has one of the small metal regulators on it that doesn't have a gauge. I've always just adjusted it until I could set a rivet in about a 1-1000 count and that's seemed to work in the past. I also use a tungsten bucking bar that came with my Cleaveland kit.
 
Bucking

A few things to try. YMMV
-Pressure needs to be set so the rivet fully sets in a couple seconds
-Relax. The bar does the work.
-Hold the gun with imdex finger pointed at the work. Use the second finger to feather the trigger.
-Tape the rivet with a piece of 3M heavy packing tape. Keeps it stable and protects the finish.
-Try a swivel set.
-Clinching. The rivet clinches because the bar and gun are not in a straight line with the shank. One or the other is off alignment. It doesn't take much. Shank will clinch in the direction the bar is tilted. It doesn't make sense. You would think it would go the other way but it tilts toward the face of the bar. Check which way the rivets are clinching and look at your position.
 
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