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Rivet question before I get to the point of no return....

Reflex

Well Known Member
If there's a prize for the most hours spent on a vertical stabilizer, I may qualify. Things have gone well, it just my lack of experience that has slowed me down. I've got a pretty good idea of what good work is, but I don't know what's acceptable so I probably spend too much time trying to be perfect. Because of this I've got a lot of time in this very simple piece. I was down to the last rivet on the top end of the vertical stab when I ran into a problem. I can't get the rivet to set flush. Below is how events unfolded.

  • Dimpled using rivet puller dimple dies
  • Used proper rivet but but head was high on one side
  • Removed rivet successfully
  • Retried to set rivet. High on same side
  • Removed rivet successfully
  • Tried to set rivet a 3rd time. Very high on same side
  • Decided hole enlarged
  • Used #30 reamer for oops rivet
  • Set 1/8" Oops rivet. Did not set well. Very poor set
  • Removed oops rivet successfully
  • Decided to post here before hole becomes unusable

I'm using a Cleaveland Main Squeeze type squeezer and the yoke I'm using appears to fit well into the small space at the shop head end of the rivet. I'm wondering if my dimple is not formed properly since I used the puller type dies due to the space restriction.

Any help is appreciated. Pictures are below:


Vertical%20Fin%201.jpg


Side%20View.jpg


Dimpled%20Hole.jpg


Rivet%20Sitting%20in%20Hole%202.jpg


Thanks,

Fred
 
I am building a 7, but in this case a suggestion, spin the deburring tool in there 3-4 times lightly to true up the countersink and check the rivet fit, if it is perfect then good to go, unless - - - unless it always fit and it setting it has caused the lifting head. No guarantee. Good luck. Oh - I am assuming you have a no-hole yoke that allows good axial alignment of the main squeeze.
 
My Opinion

I can relate to your strive for perfection. I'm on step six of the recovery plan myself:) I've re-built parts (1 VS, 1 elevator, 1 trim tab) over mistakes that, looking back, I should have just left alone and "built on". In most (all) cases, the parts that I have re-built, did not turn out perfect either.
You have done the right thing by stopping, taking a breath and asking for help. I have made rash decisions to "fix" something and next thing you know, the Van's truck is pulling in the driveway with new parts.
Your workmanship looks great and the attention to detail is obvious (e.g. nice trimming of that nose rib). You have one rivet that you are not happy with. I know the feeling. I personally don't think it will be a structural integrity issue later on. I think at this point it is a cosmetic issue. I believe you just need to get a good, mostly flush, rivet head on the skin side. It is tight quarters in there so your options are limited. Could you try and "reform" the dimple, rib included" using your pop rivet dimple die? That may help get things lined back up while re-forming the dimple. Then, put on your 3x magnifying glasses, push down on the rivet head as best you can, and very slowly squeeze the rivet. It may lean a bit, and may not be perfect, but should be good enough. It may take you a few days to come to peace with it, but give it a try:). The other option (I personally wouldn't do now that I'm on stage 6 of recovery), would be to drill the rivets for that tip rib and replace the whole thing. Chances are very high that you will end up with something that you will like less than what you have now. Then, the Van's truck may need to be called to deliver the "big box" to your doorstep!
 
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IMHO the pull dimple dies do not work well unless you pull hard enough to break the nail (or nearly so).
 
I have found that pulled dimple dies very often make a dimple that is not
centered on the hole. Sometimes is higher on one side. I think that´s what
"started" your problem.
I have done some tests with different brands of nails, and I got better results, but, a pull dimpler dimple is never as good as one made with a squezeer.

Those vise grip pliers that have dimple dies welded on the tip work better, when you can use them.
 
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Gentlemen,

Thank you very much for your replies.

BillL, I know you've been instrumental in helping a large number of people here. I value your opinion. I'm not sure I've got the skill yet to use a deburring tool on something this thin.

Bob, I agree about breaking the nail. Good advice. In fact, when the first nail broke, I didn't feel like the dimple was deep enough so I put a stronger nail in and broke it as well. The dimple was almost deep enough, so I used the same type of nail one more time and I thought I had the dimple right. This method worked very well on the other side, I guess I need to learn to work upside down!!

Shawn, I was hoping to get a response from you. I've visited your blog countless times. You're work is exemplary and I look at your site to see how you've done something almost daily. In fact if you saw my shop, I think you'd feel right at home!

At this point I agree that it is mostly cosmetic. My course of action here is just to find something that is acceptable. I'm not looking for perfection, that ship has sailed. If I'd have stopped with the first rivet and use a very small file, I'd be in great shape. I'm going to head out to the shop this evening and make my usual scrap pieces and test out a few ideas to see if I can get a rivet somewhat flush.

The first oops rivet was probably the worst set I've ever done. I'm a bit hesitant to try again until I test some other ideas on the bench.

Thanks again guys, if it wasn't for this forum, the number of completed/flying RV's would be significantly less. I hope that one of these days I have the skills to contribute and help somebody as so many here have done.

Thanks,

Fred
 
I think everyone has you going in the right direction. Just a couple ideas for future reference. You should be able to get a Tatco or other manual squeezer in there to form a better dimple. If you don't have one, time for a new tool ;) always time for new tools.
There are a few places that countersinking vs dimpling make sense and this is might be one of those. That is an .032 skin right? Dimpling a curved surface can produce inconsistent results, but so can countersinking if you have not developed those skills.

Lastly, you are being really picky, which is good. You could file the protruding rivet head carefully with a jewelers file and move on. Your finger can pick up an edge of less than .001 of an inch by feel. You could do nothing and nobody would probably ever notice.

It is nice to see so many folks on here paying such great attention to the quality of their work.
 
I feel your pain. I'm running into a similar problem dimpling the forward tip of the top rudder rib of my -9A. The pop rivet dimpler didn't give me a dimple that I liked. I tried bending the flange back a little but still couldn't get a good dimple. In the process, I may have flexed the flange too many times so I ordered another rib. I epoxied the female dimple die of the pop rivet tool to a 1/8 inch strip of steel and I'll see if that works. I can try either striking from the other side with a male die and hammer or hammer a rivet from the other side using rivet gun to get a dimple.

Cheers.
 
Two other possibilities

Cleaveland sells a couple of tools that might work. I used this vise grip dimpler in a few spots on my 9A project. It works pretty good if there's room to use it.

http://www.cleavelandtool.com/3_32-VISE-GRIP-DIMPLER/productinfo/550/#.V8ShjnCSIvY

This tight-fit dimpling fixture might also work. I've never used it, but it looks like it can get into tighter places than the vise grip dimpler. Here's a video that shows how to use it.

http://www.cleavelandtool.com/Tight-Fit-Dimpling-Fixture-3_32/productinfo/DIE4263DF/#.V8Sge3CSIvY
 
+1 on the 3/32" dimple vise grips. That is what I used in that spot. That, and the no hole yoke mentioned above.
 
After some experimenting and careful consideration, I decided that I needed a pair of the vise grip dimpler from Cleaveland. Ordered them this evening. The plan is to try and straighten out the dimple and carefully squeeze an 1/8" Oops rivet into the vertical fin.

Had I known about the vise grip dimpler, I don't think I would have had a problem. My only other regret is that I reamed the hole out with a #30 reamer. I think it would have worked better if the hole had remained a #40.

I'll move on to the rear spar and wait for the vise grips to arrive. Worst case scenario is I learn to use a jeweler's file.

Thanks again for all the advice.

Fred
 
I'll offer a few comments for the original poster:

-The way to determine if a dimple is adequate is whether the rivet sits flush with the skin prior to being driven. If it does, the dimple isn't the problem.

-In a confined space like that (and you'll find more in the flaps, ailerons, elevators, and rudder), a pop rivet (one of the MK 319-BS ones) is adequate. A well driven solid rivet would be preferable, but a properly set pop rivet is better than a poorly set hard rivet.

- That rivet is deferrable. Why not hold off on doing anything else until you get a tech counselor visit? Or until you have one of your local RV guys over to offer a hand. I'd wager that they could either help you with it, talk you through it, or do it for you in 5 minutes. A few months (and a couple of thousand rivets) down the road, that rivet will be child's play for you, so there is no need to frustrate yourself over it now.
 
When I get to a dimple I just can't get to, my favorite 'go to tool' is this one http://www.cleavelandtool.com/401-Rivet-Set-w_-3_16-hole/productinfo/Z-CF-SETHOLDER/#.V8T5wY-cGM8 with the correct dimple die.

I drilled a hole in the end of a long bucking bar to accept the corresponding male/female die that can slip into small places. A couple of light taps with the rivet gun is all it takes to make a nice dimple. You have to be very careful not to fully trigger the rivet gun or the die pounds in too far, so a couple of practice runs are a good idea.

In really tight spots (Usually where I screwed up and forgot a dimple or ten until after assembly :confused:) I have even created a female by drilling a small scrap of 1/4" bar stock steel to the rivet shank size and using a countersink tool to create the female die profile. Set the male die in the material and into the die hole and give the rivet gun a few light taps.
 
My solution to that rivet dimple was just done last week. Here's what I did.

The pop rivet dimpler was difficult to pull thru the tight hole with no clearance on the back side so I took off the dies. I then took an an426-3 rivet and pushed it thru the back of the female die. Place the rivet then thru the hole from the back side so the female die is aligned properly. The rivet head should just protrude the front (exterior) of the hole. Then place the male die on the rivet facing the skin. The rivet should hold the dies in correct alignment and position. I then took a regular pair of vise grips and squeezed the two dies together ensuring to grip the female die by the rivet head on sticking out the back side. The vise gaps made a great dimple that I then bucked with a piece of 3/16" steel bar bought at a metal supply store.

Worked great.
 
you can always just pull a Cr 3214 4-1 cherry rivet in it. That is a reduced head rivet like the nas 1097 rivet you are trying to shoot now.
 
I am building a 7, but in this case a suggestion, spin the deburring tool in there 3-4 times lightly to true up the countersink and check the rivet fit, if it is perfect then good to go, unless - - - unless it always fit and it setting it has caused the lifting head. No guarantee. Good luck. Oh - I am assuming you have a no-hole yoke that allows good axial alignment of the main squeeze.

That skin is thick enough to take some countersink. You have oviously been deburring already. Hopefully you have the Avery speed deburrer. Give it a few spins and shave a bit out of the dimple until the rivet is flush. Dont get bogged down here, build on!
 
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