[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]

ive seen the side set

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 local EAA chapter.

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]

Caution

......
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]

Not taking credit here...

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]

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?

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.

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]

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.

 

[videobobk]

Greg,

Good decision. I actually have used the vice grip dimpler very little, but don't think you will get the best dimples with it. I had a 3" squeezer head that was very slightly sprung open and wouldn't give dimples that were crisp all the way around. The side farthest from the throat of the squeezer was under-dimpled. Consider using the vice grips only when you can't get into the area with a squeezer or C-frame. IMHO the best dimples are made with your C-frame. Look at the reflection of a grid in the aluminum surface and see if the lines are straight as they exit the dimpled area. If a dimple isn't properly done, the reflections will show a waviness. It is possible to over dimple, but difficult. Good dies and technique will leave the surrounding area perfectly flat (in a perfect world, anyway.)

Bob Kelly

 

[az_gila]

Source of assembly practices

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.

After seeing how the original Orndorff tape for the RV-6 horizontal tail/fus. assembly was shown, I'm not sure of some of the construction techniques they show.

The horizontal stab. to fuselage bolts holes were being drilled directly with a large 1/2 in corded drill, the type with a side "torque resisting" handle. You can see on the video how the drill kicks as the bit breaks out on the other side of the joint.... that hole must have looked like c%*&.... and it was a final size hole.

A great example of why reamers are a good thing to use for structural bolt holes...

I would look for other sources of standard assembly practices... but you are the builder, choose wisely... YMMV.

Most other builders can get very acceptable dimpled rivets set flush without any removal of material...

gil A

PS ...I hope the Orndorff building techniques have improved since the early tapes....

 

[N941WR]

Greg,

Let's go through this riveting thing from the beginning.

1. Cleco the parts together. I liked to put a cleco in every other hole.
2. Using a sharp drill bit of the proper size, drill out the holes.
3. Move the clecos over one hole.
4. drill the remaining holes.
5. Remove clecos.
6. Debur both sides of each hole.
7. Dimple. If using a C-frame, hit that sucker hard and just once. If using the fancy thing that I can't remember with the lever, move it swiftly and form a good dimple.
8. Reassemble all the parts and put a cleco in every other hole.
9. Insert rivet, put rivet tape over the top, even if gravity is on your side. This helps keep the rivet in place on the first strike of the rivet gun.


PS. Don't forget to use the proper air pressure, if using a rivet gun.

PPS. Like you have discovered, the vice grip dimplers aren't the best. Get a set of pop-rivet dimple dies and use them. They seem to work much better.

 

[painless]

After seeing how the original Orndorff tape for the RV-6 horizontal tail/fus. assembly was shown, I'm not sure of some of the construction techniques they show.

The horizontal stab. to fuselage bolts holes were being drilled directly with a large 1/2 in corded drill, the type with a side "torque resisting" handle. You can see on the video how the drill kicks as the bit breaks out on the other side of the joint.... that hole must have looked like c%*&.... and it was a final size hole.

A great example of why reamers are a good thing to use for structural bolt holes...

I would look for other sources of standard assembly practices... but you are the builder, choose wisely... YMMV.

Most other builders can get very acceptable dimpled rivets set flush without any removal of material...

gil A

PS ...I hope the Orndorff building techniques have improved since the early tapes....

Gil:

I am sorry that you hold the Orndorffs in such low esteem. Back when I built my airplane, the Orendoff tapes were a very common source of "assembly practices".

Back to the original post......

Yes, I agree that the suggestion to use a deburring tool on dimples is not necessary. It is just another option to achieve a nicely set rivet.

Best Regards,

 

[RScott]

Your mentioning cracks bothers me. I haven't noticed any on mine. In my experience inspecting F-15's I learned that cracks usually grow from one rivet hole to another or to an edge, so this could be a pretty good problem down the road after you are flying. You don't; want to have to remove a wing skin to fix a cracked rib 2 years from now, with your pretty bird nicely painted with a $6,000 paint job.

And I didn't notice anyone answering before me who directly addressed the crack question.

So how about it, guys? Anyone know why or how he could be getting these cracks on the ribs under the shop heads?

Richard Scott
RV-9A Fuselage

 

[az_gila]

Dies

.....

And I didn't notice anyone answering before me who directly addressed the crack question.

So how about it, guys? Anyone know why or how he could be getting these cracks on the ribs under the shop heads?

Richard Scott
RV-9A Fuselage

Only a guess... but I'm voting for bad dies (or dimpling technique) extruding the inside edge of the dimples and thinning them out - since they are reported not to be over countersunk.

So my prevous recommendations to try another set of dies as a test....

Time to experiment.....

gil A