A

Anna

Active Member
Hello,

we?ve got a back riveting problem with our rudder. We went to rivet the stiffeners and all rivets got oval, aslant and sometimes with edges on its rear side. The rivet head looks perfect but the rear side looks horrible. We will have to drill out all of them. We don?t know our mistake(s). We used a back-rivet-set. We held the rivet-set perfect vertical to the stiffener. The stiffeners laid flush on the skin. Do you have an idea what?s the matter?

Thank you for your help!

Best wishes from Bavaria
Anna
 
Maybe the holes are a little over sized to begin with. If you drill them out make sure you have some nas1097 (oops) rivets on hand.
 
Post pictures!

Before you drill them out post some pictures.

Your rivets may not be perfect but drilling them out and resetting new ones
often makes things worse.
If the outside looks good you may not want to redo those rivets.
You will achieve perfection as you gain experience.
 
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I agree with Gil. Sometimes the nominal thicknesses of the metal vary and will make the rivet called out in the plans either too long or too short, depending on the thickness variations. Use a rivet gage to ensure the projection of the rivet for the shop head is OK. Also make sure the holes didn't get to big from drilling and dimpling, as Trevor mentioned.

If the rivets are not that badly set, the stiffeners could tolerate some less than perfect shopheads since they are not terribly stressed. It might be worse to drill them out as Ernst suggests. Pictures would be helpful in giving a better answer.

Roberta
 
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We took the rivet size which was told in the introduction. The smaller rivet size is to small. The clecos maintain perfect, so I think the holes aren?t too big.

Here is the best photo I took:

dsc02968muzj7h64il.jpg
[/url][/IMG]

What do you think what's the problem?
Thanks a lot for your help!
 
#1 you are not holding the back rivet set solidly on the rivet. You are missing nearly 1/2 of the rivet.

#2 you are not holding the rivet set vertical. The rivets are "laying over".
 
We hold the back rivet set as near as possible to the radius, but maybe that?s still too far away?
Maybe we should buy another one?
We held the back rivet set as vertical as possible on the stiffener, really?
But the rivets suddenly ?run? away.
On our RV Training Project it worked without any problems... :confused:
 
#1 Just to verify, you are using a back rivet set like this?

32.jpg


#2 It's possible the rivet hole is close to the flange on the stiffner. I've seen this happen and as a result, the back rivet set it pushed and part of the rivet squeezed between the plastic colar on the backrivet set and the metal. You can check to see if the center of the backset is able to sit on the rivet. If it doesn't, you might need to remove the collar or use another set.

#3 It's hard to tell, but you might be over riveting these. They don't look like they have much depth on the shop head, but it's hard to tell at this angle.
 
Double check for correct rivet length, double check air pressure at the rivet gun and if you're having a radius issue, we always shave one side of the plastic housing on the back rivet set for ease of use in a radius situation. YMMV :) Get more scrap material out and practice.
 
I'm going to guess that if you're using a back rivet set like the one in CharlieWaffles' photo, the inside diameter of the nylon ring is worn out, and is allowing the rivet tail to jamb itself between the steel and the nylon.

Once that happens once or twice, it gets a lot worse very quickly as the nylon ring gets scarred up. So try as much as practical to keep the back rivet set centered over the rivet.

So maybe a new back rivet set, or if you can get it just a new nylon ring, would probably fix this problem.

Thanks, Bob K.
 
Captain Avgas said:
Yep, that was my first thought too. Pressure way too high and the back-rivet set is just jumping all over the place.
Click to expand...

I made it almost all of the way through the wing construction at which point I bought a 4x rivet gun to replace the 2x that I had been using. Much easier to set rivets with..... the user can dial back the pressure and get a quick set.... the 2X gun required more pressure, which promotes jumping of the back-rivet set relative to the 4X.
 
TexasRV8r said:
I made it almost all of the way through the wing construction at which point I bought a 4x rivet gun to replace the 2x that I had been using. Much easier to set rivets with..... the user can dial back the pressure and get a quick set.... the 2X gun required more pressure, which promotes jumping of the back-rivet set relative to the 4X.
Click to expand...

Hmmm that's very strange. I would have thought that a 2X gun with its short stroke and low mass piston (little whacks at a fast rate) would have provided greater control on small 3/32" rivets than a 4X gun with its long stroke and high mass piston (big whacks at a slow rate).
 
I got my back-rivet set from Avery Tools and it was pre-relieved on one side to fit in tighter spaces. Aside from that, one thing that might help is to use two hands while riveting. I've seen people depend too much on the guide. One hand should be gripping the gun and controlling the trigger. The other hand should be on the guide and holding it in position. I think some people worry that the set will do to their fingers what it does to the rivet but it's perfectly safe and gives you much more control. It's the same with any set; I keep them from 'walking' by holding the end and resting the side of my hand on the work.
 
Back Riveting with C-Frame tool

I seem to recall that the rivets for the rudder stiffeners were slightly short as called out in the plans, but I might be remembering somewhere else.

As far as back-riveting, I started using Cleaveleand's 12" back-riveting set with my C-Frame tool and I love it. The link below has a nice video of how to use it. In fact, when doing my rudder, I even had one of my young kids pulling the trigger for me while I held everything in place.

http://www.cleavelandtoolstore.com/prodinfo.asp?number=RSB12

http://rivetsbythepound.blogspot.com/2011/01/rudder_23.html
 
That setup works well for control surfaces with two skins but for the models that have single-piece skins for the ailerons, elevators, and rudders, even the short set can be difficult to position at times.
 
Sometimes it is difficult to get the back rivet set such that it is perpendicular to the stiffener due to the bend of the stiffener. I have two back rivet sets. One has a wider base or a thicker collar however you look at it. I can't remember where I got that one. The other one has a narrower base. I got that one from Cleaveland Tools. It worked much better since it doesn't seem to go onto the bend of the stiffener. Like others have said check the rivet length, but you may need to fix these with some oops rivets. Don't worry if that is the case I had to use a few too. :D
 
I think your #2 is our problem, so we have bought a new back riveting set.
We will get it next week. We will try with the new one again and we hope it will work?
I?ll tell you next weekend if it does?

Thanks for your help!

Best wishes,
Anna
 
Did you try a test piece, just two small pieces of scrap metal of the same thickness, same (and different) rivet lengths, etc., with no flanges or anything in the way to obstruct your alignment of the gun, etc.?

Experimenting with scrap might be a whole lot cheaper than buying new (and maybe unnecessary) tools, reordering parts, etc. :)

If so, what were the results?
 
Hello,

We?ve good news: It works! :D All rivets look nice!

We changed our back riveting set to a new one from Avery Tools. This works much better than the old one. We think the back riveting set was the main problem? The metal riveting header was jiggling in the plastic mantle. And the plastic mantel was also obviating the riveting header to get over the whole rivet because of the radius. The new back riveting set gets perfectly into the radius of the stiffeners. The tip with the 35 psi was also very helpful.

This is the old one, the new one looks like the one on page 1:

cimg4257n31dc6brsj.jpg
[/url][/IMG]

Thanks a lot for your help!

Best wishes from Bavaria,
Anna
 
I use my C-frame for almost all back riveting. Avery sells an extension to use and the whole set up works perfectly. Also if you don't own a program that enables you to re-size images, such as Photoshop, perhaps doing a search for GIMP which is a free image editor that's is every bit as good as Photoshop could be done. Posting raw images straight from the camera is a BUMMER.
 
Back Rivet Set

I have the back rivet set you pictured, and must agree it's junk. I bought one from Avery or Cleaveland (can't remember which) and everything was great from then on.
 
Addapt the collar.

Hello

Take a file and remove a part of the collar, it is just plastic. Round the collar a bit at the bottom edge. You will use this many times when a rivet is close to a flange.

So you can get closer to the flange and be in the center of the rivet set, this should improve the situation.

Regards, Dominik
 
If you don't read anything else in this reply read this:
When using the back rivet set, pinch the delrin collar with your thumb and index fingers,
then press your thumb and index fingers down onto the rib/stiffener flange. This will capture the set so it can't skate over to the side of the collar.
Most people will press too hard on the gun making things get squirrelly.
Only put enough pressure on the gun to collapse the spring and allow the set to contact the rivet,
the rivet gun will do the work, not your hand pressure.

We have been making the back rivet tool with the narrow collar since 1994.
I think that it was Sid Golden in California that originally came up with the idea.
This allows it to get up to tight areas without restriction.
We switched from Aluminum collars to Delrin when users were concerned about scuffing primer on the parts.
We removed the flange a few years ago when Wally Anderson at Synergy started recommending our extended back rivet tool
(originally designed for back riveting top skins on wings) to be used in a c-frame.
The EAA video showing backriveting with the c-frame made the extended tool popular, but it would only work with the
Cleaveland c-frame because it could be inserted from the bottom through our unique .401 receiver bottom plate.
As mentioned we removed the flange on the collar and now the long back rivet set can be inserted into any c-frame that accepts a 1/2" ram.
We now use the same collars on the short sets.
Occasionally the 'thinness' of the collar will cause one to crack, but replacements are available and we feel the convenience is worth it.

Note that the photo for the back rivet set below is an old one as it still has the flange, but the rest is the same.

RSB35-Large.jpg
 
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