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Can double flush rivets be squeezed on TE

Barneybc12d

Well Known Member
I left a lot of tracks on the bottom of the trim tab trailing edge when I back riveted. In trying to stay away from the break in the skin (very close to the rivets) I caused numerous dents.
Has anyone tried to squeeze these double flush rivets on the wedge shaped TE with modified dies?
 
I never tried squeezing the double flush rivets but I doubt that it can be done with a hand squeezer. There just isn't enough oomph. I'm not familiar enough with the pneumatic squeezers to know if they'd work.

When you talk about leaving tracks, it makes me think you've got your air pressure set too high or you're not holding the rivet gun perpendicular (in 2 axis) to the work, or both. You really need to learn to rivet correctly if your going to finish the project. You simply can't squeeze everything. So maybe do some practicing on a non-airplane part, or get someone with experience to give you a lesson and learn the technique. It really isn't too hard.
 
I did this on my RV10.

I riveted the rudder trailing edge with the rivet gun, but I squeezed all the rest of the trailing edges with a rivet set that had been ground down to the same angle as the trailing edge.

The squeezed rivets turned out much better than the bucked rivets, but you have to be very careful to center the set on the rivet. If you have the set too far in, you will over squeeze because of the increased thickness of the trailing edge.
 
I took a basic sheet metal class at Grov-Air in Indianapolis 5 or so years ago, where we built the small section of an aileron with double flush rivets.
They had modified a flat squeezer set to squeeze the double flush rivets.

I did the same thing for both the rudders of my 7A, and the 10 that I am building now. I just sanded down a flat set so that the angle matched the angle of the wedge. I found that it works better if you partially set the rivet with two flats, then finish the squeeze with the angled set.

Good luck,
Jason
 
Tricks

Squeezing is the way to go on these skins, and especially if u have low EDs. "edge distance". You're definitely going to need a ground die to the right angle to match the wedge. A small Piece of 1/8 thick, soft rubber with a hole in it to go over the tail of the rivet will help to keep the skins together as u squeeze the rivet, and reduce, if not eliminate tooling marks.the rubber will slip out from under the rivet as u squeeze it to full shop head. I work in aviation, and this little technique has lots of millage.
 
Squeezing is the way to go on these skins, and especially if u have low EDs. "edge distance". You're definitely going to need a ground die to the right angle to match the wedge. A small Piece of 1/8 thick, soft rubber with a hole in it to go over the tail of the rivet will help to keep the skins together as u squeeze the rivet, and reduce, if not eliminate tooling marks.the rubber will slip out from under the rivet as u squeeze it to full shop head. I work in aviation, and this little technique has lots of millage.

Barron, sounds like the best way to do it. Do you have any pictures of the rubber setup? Seems like the rubber would cause you from getting a good final squeeze. I am having a little trouble picturing it. What is the best way to grind down the die? Scotchbrite Wheel? Thanks.
 
I just used a belt sander with 50-60 grit to get the angle, then polished it up with the scotchbrite wheel
 
I ground some flush dies to the right angle and squeezed them.

Here is a picture:

(click to enlarge)

I just used a belt sander with 50-60 grit to get the angle, then polished it up with the scotchbrite wheel
Be very careful doing this. You do NOT want to mix steel and aluminum parts on the same Scotch-Brite wheel. If you do, you will end up pushing microscopic bits of steal into your aluminum parts, which could cause corrosion to form later on. The same goes for sanding belts & disks, do not mix steel and aluminum on the same sanding surface.
 
The rubber can be just about anything. You wanted to be about 1/8 inch thick, or two be flush with the river tail before you buck it. Just make sure it's a soft rubber that will buck down with the rivet. I would love to send you a picture but I don't know how to load a picture on this site
 
No need for modified dies..

I decided not to modify my dies as some have suggested. I was worried that the die would rotate slightly, biting into the surface, or I'd find another equally good way to screw it up. I also didn't want to buy more dies.

Instead, I set my pneumatic squeezer depth so that it would only partially squeeze the rivets (enough to set the factory head nice and flush and hold the rivet in). Then, once I had all the trailing edge rivets partially set with the squeezer, I flipped the piece over and used a back-riveting plate and my rivet gun (with swivel flush set), set at a slightly lower pressure. The double flush rivets come out perfectly due to a good initial set and then a back-rivet quality finish set. I guess there's lots of ways to skin this cat.
 
Good Method

I just used the above described method and it works great. Didn't use any tape or bonding, just clecoed the wedge and riveted away.
 
Wow, I wish you guys had posted this 5 years ago! I would have thought the dies would slip, but results tell us differently!

I will just fill in my little smilies. (or go crazy and make a new one)

Thanks,
 
Squeezing worked great

I'm a new builder and was worried about my ability to rivet the rudder TE. Using a piece of scrap I tried riveting the rudder trailing edge using a rivet gun as described by Van's. It worked but was easy to make a mistake. Decided to try grinding down a flat die for my pneumatic squeezer to the same angle as the wedge that goes between the skins. Ran a little tape on the edge of die and up to the squeezer frame so that the die wouldn't rotate. Then tried squeezing the rivets. It worked GREAT!
Vans said to "set" the rivets on the rudder TE first, so set the squeezer a little more open which worked fine for "setting". Once they were all set then closed up the squeezer and finished all the rivets with one squeeze each.
 
Agree, this works great!

Visiting an old thread just to say squeezing trailing edges works very well, although I didn't use only squeezing like some people do. For my flaps, I kept every other hole in the trailing edge clecoed, slid the trailing edge a few inches off of the bench, then weighted down the flap skins/ribs to keep everything flat against the bench. I set the squeezer so it would bottom out just above the skin, partially setting the rivet. Once done with the "pre-squeeze" on all of the rivets, I flipped the flap over onto my back rivet plate and used a mushroom set to do the final set. I was astonished at how straight the edge ended up and how much cleaner it looked than the normal method (where I admittedly had some rookie educational moments and dinged the skins with the back rivet set when doing the first partial rivet sets). With the clecos still in and everything held flat against the table with weights, there's no need for proseal or VHB tape either, which was a bonus.

The normal back riveting method obviously works fine. The squeezer method is a great alternative though. I haven't tried grinding down a squeezer set to match the trailing edge angle, only because using the mushroom set and a back rivet plate to finish setting the rivets is so fast and simple.
 
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FYI - Cleveland Tool sells a die set specifically made to squeeze this trailing edge. Works great. ;)
 
FYI - Cleveland Tool sells a die set specifically made to squeeze this trailing edge. Works great. ;)

Yep

2016-11-18%2B11.03.16.jpg
 
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