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Riveting: Wing Ribs

R

ryschneider

Member
This is my first post on the board. I took over an RV-7 project back in June/July and I'm riveting the right wing ribs to spar. Please correct or if you have a proven technique on AN470AD 4- rivets and driving them with the ribs in that tight area... it has been a problem I can't seem to figure out at this point.
Smileys on the rib flange, damage to the manufactured head, poor quality shop head etc etc. The pressure is about 45-50 psi with a 2x gun and about 3 different bucking bars. Overall they look bad, take a long time to set and a couple have been unacceptable and I drilled them out. The ribs are in the way and I've been bending them to the side. The offset rivet set has not helped.
Ryan
 
Sounds like you have almost everything correct but are squeezing the rivet between the bucking bar and the gun. make sure the job is held firm, apply pressure with the gun and ''lightly'' touch the shop head with the bucking bar. Don't counter all the pressure you apply to the gun with the bucking bar. With me I just needed more practice.

cheers
 
Here is what I did. I used a super long rivet set (12"??) which allowed me to move the wing rib out of the way a bit as i riveted. I too have horrible success with the double offset rivet set. The first few ribs I was able to back rivet, but ultimately the best method was to set up a bucking bar rest and have a bucking helper to just hold the bar on the rest. I could then rivet using the long rivet set. I would move the rest to each new rivet location. Yes...A tad time consuming, but I promise you text book set rivets every time. When starting out, I found it helpful to hold the rivet set on the rivet head while the other hand uses the gun. Of course a bunking partner holds the bar. With enough practice you can do this by yourself. (The kicker for me is that I am only good with bar in left hand and gun in right.....so practice switching hands!!!)

http://garetsrv.blogspot.ca/2016/01/started-riveting-ribs-to-spars-7-hours.html

http://garetsrv.blogspot.ca/2016/01/more-riveting-wing-ribs-to-wing-spars-5.html
 
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Long Rivet Set

I agree with Garet. Long ~12" rivet set was the key. Also used a 3X gun. I had a good 2X gun that said OK up to 5/32 but it really didn't have enough power. Spent way too much money on a 3X but had much better results
 
I remember this well. It is a difficult area to work in. Besides bending the rib to the side, I found it necessary to grind a flat on the side of my offset rivet set. Until I did that I was not able to get the rivet set squared up on the manufactured head. Grind off as much as you need without going into the polished face and rim of the rivet set.
 
Aero_Octaveus said:
Here is what I did. I used a super long rivet set (12"??) which allowed my to move the wing rib out of the way a bit as i riveted. The first few ribs I was able to back rivet, but ultimately the best method was to set up a bucking bar rest and have a bucking helper to just hold the bar on the rest. I could then rivet using the long rivet set. I would move the rest to each new rivet location. Yes...A tad time consuming, but I promise you text book set rivets every time.

http://garetsrv.blogspot.ca/2016/01/started-riveting-ribs-to-spars-7-hours.html

http://garetsrv.blogspot.ca/2016/01/more-riveting-wing-ribs-to-wing-spars-5.html
Click to expand...

When I did the wing ribs for the first wing, I flexed the ribs to the side, just a little to get the rivet set properly aligned.

Later in the build (fuselage center section) you don't have that luxury.
If I were to do it today, I would use a short single offset rivet set with the plastic cap on it. I would also take off the retaining spring on the gun.
Another thing is to use a tungsten bucking bar.
 
Recommend a 3X gun.

And it might be helpful to use short sections of narrow fuel tube, just big enough to fit over the un-set tails of the rivets. These do a decent job of holding the flanges down. The fuel line tube expands during the riveting, comes off easily, and can be reused.

Dave
 
Thank you! I did not expect that I'd get advice so quickly. I was definitely using too much pressure against the gun. Aero, I'll be ordering the longer rivet set and try your setup as well. Thanks again!
 
For my compressor, pipe, hose setup I needed 80 to 90 psi for -4 rivets with a 3X gun, but your setup may be different. I used an offset cup rivet set, ground one side flat as mentioned earlier, then put a small piece of masking tap over the tip of the cup set. The tape keeps the offset set from rotating. What really helped was a second person bucking while I shot. I could hold the gun and set to keep it on the rivet.

Keep in mind longer sets and offset sets loose more energy than stubby sets...need more pressure.

Also, in the wing walk area, rivet the ribs to the main spar before the rear spar, as I did not have room between those ribs to fit a gun.
 
Alternate method to rivet main ribs to main spar

I did it totally different. I back riveted them. Detailed in my blog and a tip I submitted to Kitplanes.
Set the spar on benches with the rib up.
Prop it up on either end with blocks high enough so the back rivet bar fits underneath. I actually placed the round back rivet bar bar on top of a back rivet plate then placed a tungsten bar on top of it. More mass and the tungsten is nice and square.
Now add some pliable material to the end blocks like foam. You want the set up just high enough so the rivet shop head is not contacting the bar.
Adjust every time so as the shop head is driven, the bar will not touch anything. Check again. You don't want any damage to these parts.
Gently flex the rib over and drive the rivet. Easy Peasy and perfect shop heads.
 
Last night I had better luck with the riveting. I used some heavy tape over the head of the rivet for protection, however the snap soc looks like they might be very useful. I riveted in shorter bursts and that seemed to help while holding the tungsten bar more loosely. I lowered the psi to 40ish and removed the regulator at the gun. You guys are awesome, I'll contribute as I learn, thanks!
 
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