I need some reassurace

[ditch]

I'm looking for that pat on the back now and the words, "its ok and will be alright." I'm talking about the simple task of riveting. What I'm having trouble with is looking closely at rivets after I've bucked them. I could swear that some look like they are not holding any of the metal parts together. Is it an optical illusion or can the riveting process actually spread the holes wider than they should be? I guess that some rivets I buck look fine but when you really get down and look closer at them, it seems like one side of the dimple is holding more than the other or the rivet is'nt gripping any of the dimple even when it's bucked. I know that some are just an illusion and they are fine but some I would swear are not going to do their job. I also have noticed on a couple ribs in the wing that after the rivet is bucked, they will have a tiny crack on the dimple from the bucking. The rivet is driven straight and to the right depth and still there looks like a tiny crack is there. I have had a couple where I have drilled them out because they were bucked wrong and found a pretty good crack starting in the dimple of the rib. Had to de-burr the crack and put in an oops rivet to hold the skin. Anyone else notice small cracks or what looks to be cracks? I'm not dimpling to hard and all in the ribs are done with a vice grip hand squeezer anyway. I keep feeling that if even one rivet lets loose the wing will fall apart. I know its dumb but would like to hear if anyone else has really looked closely at the shop heads and felt the same way. It would be nice to hear from someone who has had theirs flying for some time now and that it's ok. Are these things kinda overbuilt anyway?

[cytoxin]

at least thats what i call it. but if you drill most of them out you'll find an impression all the way around on MOST of them. i have not noticed the cracking and i look pretty dern close. i have dimple once twice sometimes even three times..1-2 turns Preferably ONE with the debur bit with no pressure. i found one good whack with the white uhmw hammer produces nice dimples.. then there's the drdt deal which i hear works flawlessly.
stop the cracks they wont cause the wing to fall apart but they will aggravate the **** out of you later when you have to start raplacing stuff.
good luck....

[painless]

This is one of the many times you will need to step back away from the project and just take a breath.

I suggest that you do some practice dimpling/riveting to boost your confidence before you go any further. Get some scrap together and rivet a bunch of it together, and try to do the best you can.

One suggestion that I have that will make your rivets sit better in your dimples is to take your deburring tool and spin it a couple of times in each dimple. This will sort of "countersink" the dimple and flatten the slightly rounded surface the dimple die will leave. Don't go crazy here with the deburring tool....just a couple of revolutions will do it.

Another thing you can get in the habit of doing is to set your parts together before you actually set the rivet. Hold your bucking bar just to the side of the rivet and then with a swivel set, run your rivet gun one or two taps on the rivet. This will help to ensure your parts are sitting flush and tight against each other. Don't sit there and run your gun for several seconds. More is not better in this case. Just one or two taps. Then set your bucking bar on the rivet and set it with your gun.

Also, make sure you are not pressing so hard on your bucking bar before you set a rivet that you are actually lifting the rivet out of the hole. Keep firm pressure on the gun over the rivet and then set the bar on the rivet.

Lastly, is there anyone in your area that could take a look at what you are concerned and offer you their opinion?

I hope all this helps. Hang in there.

[videobobk]

This might just be one of those occasions where an EAA Tech Counselor could tell you what you need to hear. There are three guys in your state who have volunteered their expertise to you, free. It sounds like something where a set of trained eyes could give better opinions than those of us just reading about it. Check out TC's at the EAA website. I am assuming you are an EAA member.

Bob Kelly

[jdeas]

Find a EAA Tech Counselor before you close your first parts up. I had the same feelings when I started. In my case under dimpling was causing 'quality issues'. At any rate it will calm your fears. An hour with a EAA guy will save you days of worry as you start your project.
Worst case take a sample of your work to a local EAA chapter. Chances are someone there will be more than happy to help.

[az_gila]

Originally Posted by painless

......
One suggestion that I have that will make your rivets sit better in your dimples is to take your deburring tool and spin it a couple of times in each dimple. This will sort of "countersink" the dimple and flatten the slightly rounded surface the dimple die will leave. Don't go crazy here with the deburring tool....just a couple of revolutions will do it.

........

There should be absolutely no need to do this. Even a light spin is actually taking material out of a structural joint.

If you think this helps, then look at the rest of your dimpling process, or buy some new dies....

The EAA Technical Counsellor suggestion is the way to go... get used to effective dimpling, riveting early in the process.

gil A

[painless]

Originally Posted by az_gila

There should be absolutely no need to do this. Even a light spin is actually taking material out of a structural joint.

If you think this helps, then look at the rest of your dimpling process, or buy some new dies....

The EAA Technical Counsellor suggestion is the way to go... get used to effective dimpling, riveting early in the process.

gil A

This was a suggestion/tip that was gleaned from the Orendorf construction tapes that I viewed.

The amount of material that is removed is so minimal, that I highly doubt that any structural integrity is lost.

My dies were new BTW, I really don't think my dimpling technique was lacking, and I saw a difference in how the rivets set.


As always, YMMV.

[Gsuit]

Originally Posted by ditch

I could swear that some look like they are not holding any of the metal parts together. Is it an optical illusion or can the riveting process actually spread the holes wider than they should be?

Originally Posted by painless

This is one of the many times you will need to step back away from the project and just take a breath.

I suggest that you do some practice dimpling/riveting to boost your confidence before you go any further. Get some scrap together and rivet a bunch of it together, and try to do the best you can.

Originally Posted by videobobk

This might just be one of those occasions where an EAA Tech Counselor could tell you what you need to hear. There are three guys in your state who have volunteered their expertise to you, free.

Greg,

Ditto to the above quotes. I would add, when you do the practice riveting, find a piece of test scrap that has a few rivets that look like the one's you worry about - and try to tear them apart in a vice with pliers, hammer, chisel, etc. Once you do get them apart, and as your breathing subsides back to normal and with sweat pouring off of your nose - you'll realize these things freakin' are not going to let go!

[Mike S]

Originally Posted by ditch

but when you really get down and look closer at them, it seems like one side of the dimple is holding more than the other or the rivet is'nt gripping any of the dimple even when it's bucked.

If what I quoted above is referring to the factory head, not the shop head, I think I can help you a bit.

When you squeeze/shoot a rivet, you are performing two actions. These happen in the following sequence.

First you are expanding the shank diameter of the rivet.

Then, you are creating the shop head.

The rivet holds the parts together in two ways, first, the expanded shank grabs the inner radius of the hole, and second the shop head clamps the parts between itself and the factory head.

If the rivet is not all the way in the dimple before you start the shooting/squeezing process, the expanding shank will grip the hole so hard, that the rivet will not seat into the dimple.

Go re-read the advise from "Painless", he makes some good points here.

Remember, all parts must be in good contact before you rivet. This includes the parts-----skin/rib (or whatever) and the rivet. Do not depend on the gun to force parts into contact.

Also, just to be sure, are you clecoing every hole prior to riveting??? Remove a cleco, shoot a rivet it that hole, remove the next cleco------ETC. (Exception here is back riveting)

In areas where the parts dont want to lay flat----leading edge to rib is a prime example, even the clecos may not be enough to keep the parts together as they should be prior to riveting. I have make good use of plastic faced clamps here, and sometimes I have had to use a third hand to push down on the skin before shooting a rivet.

Good luck.

[ditch]

Actually after I posted this thread I saw someone with the exact thing happening to him. He posted a picture and it was the same problem. The shop head is what is causing the crack and I think I may have figured out at least part of the problem. I used a vice grip dimpler and when I close the pliers the dimples don't interlock perfectly, they leave sort of a off dimple with one side deeper than the other. I bet that's why some of the rivets want to lay over sometimes and not form a nice shop head. Any way, I called the FAA today to see if an inspector would come out and take a peak at it, turns out, I met this guy at the EAA meeting 2 weeks ago and he said he'd be glad to come out this week sometime and look things over before I move on. I am just about done with the left wing and ailerons and flaps are completed so it's not for a lack of riveting and I don't think the technique I use is the problem. It's only a couple that have done it but I still get upset trying to figure the problem out. I'm not trying to make a show plane but I definetely want it to be a safe plane. Hopefully this inspector can make me sleep easier at night. Thanks for all the help.