Need some advice on these rivets

[WVM]

Hi,

Yesterday a friend helped me with riveting the inboard ribs of the horizontal stabilizer on the frontal spar. I am not really happy with the result and I keep on thinking about it... What should I do with it?

I rather don't have any parts in my aircraft of which I don't have a good feeling. This is one of them. I have contacted VANS about it. They told me that it doesn't look pretty, but that I probably do more damage with drilling everything out, than leaving it. This is a bit double, because actually they are saying it is not good. Main problem is that all six are damaged, it is not just one of them.

Other question I have is, that if I drill it out, would there be a way to do it better? Would a 4 inch yoke be able to set them? I tried with the 3 inch, 2 inch and "spar" yoke, none of them worked, but I don't have a 4 inch at the moment.

I really would like to have your comments on this. Do you also have those in your aircraft? How do they evolve over time? Am I maybe a bit to worried about nothing? ...




Thank you!

[sahrens]

I am not going to disagree with Vans.

You have some damaged rivets, but you also have damaged the aluminum sheet around the rivets. I believe that is the spar doubler to the right of the six rivets you are questioning. Almost every one has damage around the rivet. Those "smilies" around the rivets are caused by either the rivet set not squarely on the rivet head or you are using the wrong cup rivet set.

I realize you are not in the US, but if you download a copy of FAA 43.13 and look at page 4-58 you will see what I mean by wrong cup rivet set. If the cup is too large part of the force during riveting is on the skins, which makes those small curved indentations. The more likely problem is the rivet set is not squarely on the rivet, which will also make those marks. I would guess your rivet tails may not be completely square as well.

I suggest you get some scrap material and work on getting the rivet set squarely on the head and tail of the rivet. Do as many as it takes to be able to see and know the rivet set is squarely on the rivet. Then drill out those practice rivets to learn how that works. That will be faster than drilling out multiple bad rivets on your project and you will be happier in the long run.

Look at your first image at the spar doubler, top row, second rivet from the left. The goal is to try to have them all look like that one.

[MercFE]

They certainly aren't pretty... But they look like they'll do the job.

Getting to those rivets is kind of tough, given the angle that the inboard ribs are at. I used an offset rivet set and a tungsten bar to get at them. I wasn't able to figure out any way to possibly get a squeezer in there.

The rivets that Scott are talking about, in your spar attachment points, show a lot of the same indications of the rivet set not being square. I used the squeezer on those rivets in my plane, but they help to suggest that you work on some scrap material a little bit more for practice.

You should strive for all your rivets to wind up like the top-middle on in your first picture, like Scott said. However, they probably won't all be that way.

If you had one bad rivet in the rib, I would say give it a shot. But drilling out and replacing all three, when they all appear to be functional as is, is just asking for the possibility of more damage.

[Lionclaw]

Mine looked almost exactly the same. I drilled them out, but the replacement ones ended up mostly the same. Since then I've gotten better with the offset rivet set and I learned a trick--put 2 layers of masking tape or duct tape on the end of your rivet set.

Here's how my RV-10 rivets ended up in the same location.

[sahrens]

Andy those are really nice. Excellent work. I wished all mine looked that good.

[wirejock]

I agree with Scott. Drilling them won't fix the damage to the doubler. If Vans is ok with them, leave them for now. Maybe when you get past the wings and you have total confidence in drilling rivets, drill the doubler out and replace.
For now, move on and practice. Use a piece of Gorilla tape over the rivet to protect from smileys. I set those with gun and tungsten bar.

Don't stress. I egg shaped one hole drilling rivets for the HS Service Bulletin and had to drill the entire HS apart to replace the forward spar. Glad it happened now but I was really mad at the time. Drilling 500 rivets gave me confidence.

Drilling rivets is a technique. Search or ask how to do it.

[WVM]

Originally Posted by sahrens

I am not going to disagree with Vans.

You have some damaged rivets, but you also have damaged the aluminum sheet around the rivets. I believe that is the spar doubler to the right of the six rivets you are questioning. Almost every one has damage around the rivet. Those "smilies" around the rivets are caused by either the rivet set not squarely on the rivet head or you are using the wrong cup rivet set.

I realize you are not in the US, but if you download a copy of FAA 43.13 and look at page 4-58 you will see what I mean by wrong cup rivet set. If the cup is too large part of the force during riveting is on the skins, which makes those small curved indentations. The more likely problem is the rivet set is not squarely on the rivet, which will also make those marks. I would guess your rivet tails may not be completely square as well.

I suggest you get some scrap material and work on getting the rivet set squarely on the head and tail of the rivet. Do as many as it takes to be able to see and know the rivet set is squarely on the rivet. Then drill out those practice rivets to learn how that works. That will be faster than drilling out multiple bad rivets on your project and you will be happier in the long run.

Look at your first image at the spar doubler, top row, second rivet from the left. The goal is to try to have them all look like that one.

It is actually the damage around the rivets that I am talking about. The rivets itself are not that bad to my opinion. According to the builder how set those rivets for me the reason is the offset rivet set that seems to turn in between two hits of the rivet gun.
I had to attach the assembly with the lead on the elevators and don't have this damage, but I really hate to set those rivets with a gun. Would it work with a 4 inch yoke to set them with a rivet squeezer? Tomorrow I have an inspection planned from the aviation authorities. I am going to see what he is going to say about it.

[WVM]

Originally Posted by Lionclaw

Mine looked almost exactly the same. I drilled them out, but the replacement ones ended up mostly the same. Since then I've gotten better with the offset rivet set and I learned a trick--put 2 layers of masking tape or duct tape on the end of your rivet set.

Here's how my RV-10 rivets ended up in the same location.

Hi Andy,

That indeed look really nice! Would you have a picture of the rivet set because I am not 100% sure that I understand how you put the tape around it.

[WVM]

Originally Posted by wirejock

I agree with Scott. Drilling them won't fix the damage to the doubler. If Vans is ok with them, leave them for now. Maybe when you get past the wings and you have total confidence in drilling rivets, drill the doubler out and replace.
For now, move on and practice. Use a piece of Gorilla tape over the rivet to protect from smileys. I set those with gun and tungsten bar.

Don't stress. I egg shaped one hole drilling rivets for the HS Service Bulletin and had to drill the entire HS apart to replace the forward spar. Glad it happened now but I was really mad at the time. Drilling 500 rivets gave me confidence.

Drilling rivets is a technique. Search or ask how to do it.

I did not yet set the rivets in the ribs on the other side of the spar. If I would replace it, I would simply reorder a set of 4 ribs, 2 nose and to inner ribs. Eventually with the spacer. The only drilling that needs to be done is the 6 rivets and the nose rivets. I am quite confident in drilling out rivets as I did so a lot already, but I need a better technique to redo it when I drill them out. I was hoping that some had experience with the 4 inch yoke on those? The 3 inch, 2 inch and special spar yoke don't work because the skin is always in the way.

[az_gila]

Originally Posted by WVM

...
According to the builder how set those rivets for me the reason is the offset rivet set that seems to turn in between two hits of the rivet gun.
....

Either hold the rivet set with your other hand or use duct tape to tape the rivet set to the rivet gun to prevent turning.