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rivet problem - need advice

lostpilot28

lostpilot28

Well Known Member
I think I need to upgrade to a better quality squeezer, because I think it's flexing when I squeeze rivets. I've attached a couple of pictures of some rivets on my left elevator and I'd like to get some opinions on what I should do.

My concern isn't that they're not pretty, but that they may not be strong. Basically, no matter how straight I try to hold the squeezer the shop-heads end up squeezing more to one side of the hole leaving the other side unattached to the rivet. I've drilled a few out and replaced them and they look like little feet instead of nice, round mushrooms.

Do I need to start drilling all these out? Any advice is greatly appreciated.

Regards,
Sonny W.
RV-7A empenage

1a.jpg

2a.jpg
 
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You're right. Those don't look so hot. (the camera always makes things look worse than they are). Maybe some more practice with the squeezer is in order. Try experimenting with squeezing off center a number of ways (just a hair). Pneumatic or hand squeezer? The yoke does flex a bit. The bigger the yoke, the more flex.
 
Concentrate on holding the squeezer EXACTLY perpendicular to the rivet. I doubt this is a fault of your tool. Those rivets look a little undersqueezed to me. I would not replace the ones you have shown us, but give them a few thous more squeeze (after you measure the shop heads and verify my observation, natch). Better is the enemy of good, rivets don't have to be perfect, and you can cause more trouble for yourself drilling out less than perfect rivets. Really, those look like airworthy shop heads as is. Good luck.
 
I had similar problems with rudder skin against main spar (stiffener and it's rivets blocked perfect access to some of the rivets). I concentrated too much to the shop head side and tried pretty much everything. I managed to do more bad rivets than even since in very short time. Then a time out -- now I tried again, but didn't look at all at the shop head side (of course, I had already correct shop head height adjusted). I went to the manufactured head side, put the squeezer as well to the center of manufactured head as possible, then looked that squeezer was perpendicular to the rivet and squeezed. There must be numerous ways to check the perpedicularity of the squeezer, I do it by looking the mirror image which is reflected from the skin (anything perpedicular to the mirror should like going through it without making any angle at point of "touch"). So far with good success. After this the hardest rudder rivets went fine.

It's possible that the cheapest squeezers/yokes bent more than expensive ones but there are numerous ways that the user can do it by itself. :( So before going to buy new tools, try different methods. If you have smaller yokes which has access to those rivets, try again with them. Longer yokes are more likely to bend.

I will not comment about drilling those out more than I would do so, if they are in critical place. I wouldn't say they fulfill mil. spec. so if that is what you are following, start your drill....

It would be very nice to know how much rivet like that can hold compared to the rivet done according to the mil. spec. How big difference rivet like that can make?
 
What squeezer and yoke you using?

I would say you need to drill them out because you have several clubed over in a row. One here and there I would not worry about but an entire row of them would make me nervous.

I also noticed from the pics that it does not seem like (can't tell for sure in a pic) you have debured your edges. This can lead to cracks later down the road.
 
It's important to get the rivet centered on the die to avoid this problem. The other big thing is to use the smallest yoke that will reach. The deeper yokes definitely flex quite a bit.
 
I would also double check that you are using the correct length. If they are too long, they tend to bend like the ones in your photo.
 
Maybe old rivets

My best guess is that either the rivets are a little old and hard or that you should try one 1/2 size shorter. I found the 1/2 size different to fix many squeezing issues where the full size just wasn't quite right. Just check the dimensions of the shop head when its done to make sure you are within specs.

Tom
 
I had a similar problem with my pneumatic squeezer with a 3? yoke.
This is more likely to happen if the rivet is a bit too long. I find that it helps if the rivet is located close to the inside edge of the dies when squeezed. I discussed this with Cleaveland Tools some time ago and they said that if the die surface is too slippery it can force the rivet to slide and therefore bend over when squeezing. The recommendation from Cleaveland was to keep the dies clean and to rough up the polished die surface slightly.

Fin 9A
Australia
 
gbrasch said:
I would also double check that you are using the correct length. If they are too long, they tend to bend like the ones in your photo.
Click to expand...
I think Glenn is right on here. 9/10 times when this happens to me it was because the rivet was slightly too long. Buy a rivet cutter for $10.00 and you will easily get your money's worth out of it. Other than not holding the squeezer square, I don't think there is any other source of your problem. Good luck.
 
Rivet problems - reply

Hey guys,
Thanks for all the replies...I appreciate every one of them. Here's my attempt to answer all of the questions & comments:
- The squeezer is a hand squeezer from Avery. It's the cheap 3" Stainless Steel squeezer.

- the rivet lengths are a hair too long, but if I go 1/2 size shorter they seem much too short. They're really close to being correct length, as is.

- I thought the rivets may be old, but they're the ones I got with my kit 3 months ago. I thought it may be the cold weather, too, because it didn't start doing this until it started getting cold recently.

- Regarding the "under-squeezed" comment, I have the Rivet Reader from ACS and they actually come out within spec...it's just the "clubbed" look that bothers me.

- About the deburred edges, are you referring to the rivet holes? I do debur every one of them prior to assembly, but I've noticed that they look a little rough in the close-up pics. They feel smooth, however. If I debur them any more they will start to counter sink (I've done that a few times on the practice kit). The straight edges are deburred, too...except for that hinge-cutout (U- groove) which I haven't gotten to yet. It's on my list, though!

- I will try roughing up the dies just a bit...the rivets may be sliding.

- I do hold the squeezer perpendicular, but the clubbing still happens. I've tried various slight angles, too...some work better than others.

Just another thought - all of these "clubbed" shop heads are on skin-to-spar areas (mostly on the elevators). That's really the only place I've been having this problem. I'd rather not drill them out because I don't want to cause more damage by drilling, but if I have to then so be it. ;-)

I've gotten a few "they look airworthy" comments and a few "start drilling" comments...I'm still a little unsure of what to do. Zoiks!

Again, thanks for all the great replies...I'm looking forward to the next few!

Regards,
Sonny W.
Boise, ID
 
Are you sure that when you start to squeeze them you maintain the alignment? I think it would be easy to unknowingly move the handle that should be stationary a little when you start the squeeze.
 
as others have said:

looks a bit undersqueezed
looks like some edge deburring needed
trying for too much perfection can result in poorer rivets and enlarged holes, which then exacerbates problems getting rivet to set.
i don't think flex is causing this

I think key problem is that squeezer shaft is not perpendicular to skin (parallel with rivet shank). They all look consistently the same, so that's good. I'd say you're tipping the squeezer. Try tipping the squeezer so fixed set is a bit more in teh direction that all these are laying down in.

If not a pneumatic squeezer, you may find it easier to do with a pneumatic. They cost more, but easier to work with. You can easily hold work in one hand and squeeze with the other.

Other tips:
I use the moving set (the one on the shaft, not the one on the yoke) against the mfg head. Press it against the rivet head. Look closely at the rivet set against the skin - should be same gap all around. I use magnifying goggles when i do this. Make sure set is centered on head. If pneumatic, squeeze it slowly-don't just jam the throttle open. You can also help check proper alignment by seeing that fixed set (the one on the yoke) is coming onto the rivet in its center. If your moving set is centered and your fixed set is centered, you must be in proper alignment. With practice, you can do it just by looking at the moving head. If centered and even gap all around its edge, tehn your fixed set must be in proper location, too. All this is easier with pneumatic. If you don';t have one, lots of much lower priced ones on ebay every day.
hope all this helps and good luck with it,
brian
 
Me too

Sonny,

I have had the same problem with a pneumatic squeezer too. Including the crinkled looking metal right next to the shop head, which makes it look like you didn't deburr. When I see this, it is my first clue that the rivet clinched. I first encountered this while riveting the HS spars together for an RV9. I still don't have it figured out yet, except that I seem to have better luck with my 3" yoke than with the longeron yoke.

I'm located about 50 miles down I84 from you in Fruitland. If you want to chew the fat about this, give me a call at 452-3795. John Siebold lives in Meridian, I think, and would probably be willing to help you out if he sees your posts.

Redards,
James Jenings
Fruitland, ID
RV9, N94JJ reserved
 
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I know that there are several disbelievers, but I'm almost certain that yoke flex is most of the problem here. If you set a rivet in a non-dimpled hole, the hole fits so closely around the rivet that it's almost impossible to screw things up. On the other hand, a dimpled hole, coupled with a rivet that's a hair on the long side, is almost guaranteed to bend if anything gets out of line. In fact, based on the picture, they all just happen to be bent in the same direction, which just happens to be the direction they would bend as the yoke spreads a bit.

Try this experiment:

Using your three inch yoke, carefully center a short rivet on the die. Now, while holding the squeezer vertically, give things a good squeeze while watching the rivet from the side. If it squashes pretty straight, move up to the next longer rivet. Continue this until the rivet is so long that it bends over.

Now do the same thing with the one inch yoke. I'll bet you my cleco collection that the shallow yoke will allow a much longer rivet to be squeezed.

Oh, and things get even worse with number 4 rivets. I use the one inch yoke for everything unless it won't reach.
 
I have had trouble like this before. My problem was that the work was flexing (twisting) as I applied the squeeze.

Also, if when you insert the rivet it feels somewhat loose, you might try pre-squeezing the rivets just slightly so they fit more snuggly.
 
Some thoughts.

I had problems with the first squeezer tool I bought. Purchased another and the golf club heads went away. The problem I had was that the tool flexed. I did two things that helped. One was to use smaller dies. This made me keep the rivet in the center and almost fixed the problem. It showed up more with larger rivets because the tool flexed more. Second once a rivet hole has been drilled I do use a larger rivet (OOPS rivets). I am afraid of smoking rivets caused by loose rivets in the old hole. It is also easier to screw up the second rivet because the hole allows the rivet to not be set straight and tight. The rivet gun always works well now that I have learned to handle that well. :) Have fun. Things look good now that I have learned a little.
 
Thanks guys - last question

Thanks again. From what I can tell I really should get a 1-1/2" yoke (or maybe a 2" yoke) and see if the problem goes away. I'm very careful to not move the squeezer fore, aft or side-to-side once I start squeezing. The one thing I don't pay attention to is if it is twisting...I don't think it is, but I'll keep an eye on it. I really do think it's a yoke-flexing problem, though.

My last question I need answered is this - do you think it's a structural problem to leave these rivets as-is? Should I drill them out, drill out only the really bad ones and don't worry about the "just OK" ones, or just leave it alone?

Best regards,
Sonny W.
 
my .02

1.use flat dies
2. the shortes rivet that will acheive the proper shop head
3.the shallowest yoke avail.
4 make sure your holes are not to big.
as far as squeezing off center, i do that all the time on 7+ rivets. works like a charm. by this i/we mean place the tip of the rivet a teeeeeeeny bit towards the throat of the yoke.
does look like some more deburring is in order on some of those edges.
cant say that the yoke flex os the problem though i use a 4 inch one alot. with out any troubles. never seen the 3s give this problem.
good luck
 
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szicree said:
Try this experiment:

Using your three inch yoke, carefully center a short rivet on the die. Now, while holding the squeezer vertically, give things a good squeeze while watching the rivet from the side. If it squashes pretty straight, move up to the next longer rivet. Continue this until the rivet is so long that it bends over.

Now do the same thing with the one inch yoke. I'll bet you my cleco collection that the shallow yoke will allow a much longer rivet to be squeezed.
Click to expand...

Well, I just did this. Here's what I learned: The 1" yoke will do up to a -5, but the 3" only goes up to a -4 without bending the rivet. I did all this without any surrounding material -- just the rivet. Any tendency to bend is greatly exagerated when the rivet is all by itself. I also adjusted the dies so that they would meet and tried to see how much force it would take to spread the yoke a bit. With the 1" it's about impossible, but the 3" spreads quite easily.

I also tried squeezing with the rivet off center on the dies and I found that it's extremely sensitive to centering. My dies are slightly crowned and I believe this is what makes the centering such an issue. My yokes are Tatco and I think all my dies came from Avery.

In summary, I'd say that centering is by far the most important thing, followed by yoke flex. If the yoke is flexing you could compensate by placing the rivet slightly further inside the yoke. You might also adjust things so the dies are touching and make sure the crowns are centered on each other.
 
So much has already told here so this may even be on list already, but as you said that the problem is with skin to spar rivets that rings my bell with the issue that at least if I pushed squeezer too hard against the surface, the skins and spar actually bent a bit and this might twist rivet and you know the rest.
 
More Pictures - Interesting

So I tried the experiment today and I notice something that I hadn't noticed before. My yoke die is slightly misaligned from the squeezer's die. Notice the first picture below. I question whether that's the problem, though, because the dies are slightly curved. Any misalignment of the face of the dies won't matter because of the curve (hold 2 tennis balls together but slightly misalign them - you'll see that from the perspective where they touch, it's still as flat as it can be). Then again, dies aren't round like tennis balls, either, and my squeezer's misalignment looks like it's more than the curve would compensate for.

I really think this is a flex problem now...when the rivet is moved aft (into the throat) the clubbing is less. The "centered" rivet in the pictures is squeezed a little less than the other 2, which is why it isn't clubbed as bad as the middle one. I think I may just buy a 1-1/2" yoke and see what happens.

Any thoughts? Still hoping for some advice as to whether to drill all my bad rivets and replace them. Thanks!

Regards,
Sonny

3.jpg

4.jpg

5.jpg
 
Cleaveland Main Squeeze!!!!!! Throw that thing away now! Why ruin your 80K project (not to mention all those sleepless nights) With a p.o.s. like that? You will end up with a pneumatic squeezer anyway, so you should have a manual squeezer where you can interchange the yokes between the two. If you could try them all, you would probably pick the Cleaveland!
 
Get a new squeezer!

I believe that the apparent misalignment of the dies shown in the first photo would pretty much guarantee a problem. I suggest a pneumatic squeezer with good solid yokes, and Cleveland dies. I own only the pneumatic and wouldn't trade it for anything. It allows you to use both hands for steadying and alignment, and when you get things looking the way you want, zap, it's squeezed right now. I can see some angle to the shophead when using the deep yokes, but nothing like the "clubbing" you've got. Pneumatic or hand powered, I'd get a new, high quality squeezer and yokes.
 
Concur with Capt Ron and William. I've got both the "Main Squeeze" and a pnuematic and they are not nearly as sensitive to horizontal alignment. In fact I just squeezed some rivets on my HS that due to interference from the rib that I was riveting required the die to be off center and it squeezed just fine. Vertical alignment is crucial though. Cant the yoke off vertical and you can pretty much bet on a goofed rivet. Quality tools are expensive, but last longer and produce superior results.

Todd
#40631
Riveting HS rear spar
 
Thanks fellas...would you recommend I drill the old rivets or leave them alone?

Also, my hand squeezer is actually an ATS squeezer (I thought it was Avery). It does have a lifetime warranty and ATS is going to send me a replacement today. I'm going to see what happens with the new one...if it doesn't improve the results I'll spend the money and get a Main Squeeze.
 
I'd drill'em. Extra work, but I think you'll be happy you did. For what it's worth, the bulk of my tools are also ATS. Got a good deal from them back a few years ago on a customized kit. But I've bought from just about everyone--Avery's, Cleaveland, and the Yard Store, to name a few.

Todd
#40631
 
I'll add some more chaff to this pile. I had a "Main Squeeze" when I started my project, and no matter how much I practiced and analyzed, I couldn't form a decent rivet. I quickly (after many days and hundreds of rivets of practice) abandoned the manual squeezer for a pneumatic and never looked back. The pneumatic squeezer arrived and I was immediately forming nearly perfect rivets every time. I was amazed. I never did figure out the hand squeezer and sold it.
 
Avery Hand Squeezer and Right Size Rivets

If the rivets are too long thay will clinch over instead of being squeezed and if the die faces are not perpendicular to the center line of the rivet initially or during the squeeze they will not clinch over but they will squeezed to one side. Yours are being squeezed but the shop head is being forced to one side. If you suspect your squeezer is flexing during the squeeze and causing this problem I would not hesitate to make a change. With my Avery hand squeezer I can feel the rivet taking a set and I know without looking when tight quarters have caused a bad set or an excessively long rivet has clenched. With care I have set long rivets to fill a drilled out rivet hole using the squeezer that that I could not have set with the gun and bucking bar. It is a wonderful tool if it is a good one. You should never see recurring rivet installations like you show in your photo and you are right in trying to solve the problem.

Bob Axsom
 
What type squeezer?

The photos seem to show that the ram guide is independent of the rest of the yoke in your squeezer. IF that is the case, I am sure the roll pins will not be able to maintain alignment of the yoke when loaded and the upper rivet set will do exactly as you see in your photo.
The other squeezers mentioned above have the lower ram guide tube integral with the yoke so the rivet sets' lines of action have a better opportunity to remain collinear.

-mike
 
I'd drill the worst ones out and replace. As you know, things can get worse when drilling out rivets, so be careful. You'll probably want to slightly pre-squeeze the replacement rivets.

Mike: Wow, I hadn't even noticed that. I'd say that's the trouble right there.
 
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as said

toss that squeezer get the avery or like with yokes that canbe used in pnuematic squeezer (cause you'll want one of those next) the only time i use those crowned face dies is for a spot where i could have machine c/s a thou or two too deep. that mis alignment is multiplied by those crowned dies. get the flat dies at minimum and yes i would drill them out. use a smaller bit than a 40 drill just deep enough to snap the head off of the rivet then finish drilling through and push the shank out. do all aver again. be warned that once a rivet sets in this thin material the hole is enlarged even without drilling it all the way through. and this then makes it even more difficult. oh yeah deffinately get a set of cutters. worth their weight in gold esp. if you are priming.
 
One more tidbit

When you use a manual squeezer, use the non moving handle to stabilize the tool, and the alignment of the tool/rivet, bring the moving handle to the fixed one, do not just squeeze the two handles together. This will help keep the die centered on the shop head.

Takes a bit of practice, but it can be learned.

Also, sometimes a flange/longeron yoke can help when riveting close to an obstruction, instead of trying to work where you feel the need to tip the squeezer to get clearance.

Mike
 
mlw450802 said:
The photos seem to show that the ram guide is independent of the rest of the yoke in your squeezer. IF that is the case, I am sure the roll pins will not be able to maintain alignment of the yoke when loaded and the upper rivet set will do exactly as you see in your photo.
The other squeezers mentioned above have the lower ram guide tube integral with the yoke so the rivet sets' lines of action have a better opportunity to remain collinear.

-mike
Click to expand...

I'm sure Mike is right on this. But I'm a bit confused; You say it's an ATS, but they don't show this one in their catalog. Forget the lifetime guarantee, unless they will replace it with an improved-style squeezer where the ram goes through, and stays aligned with the yoke.
---------------------------------------------
I did find that squeezer in the catalog after all, but it is the style that doesn't allow the ram to go through the yoke. The Tatco style (stainless steel) which lists for about $20. more would be a much better choice.
 
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OK - trading up

Alright guys...I took your advise (at least a little bit) and called ATS and cancelled the order for the replacement squeezer and upgraded it to the one with the ram that goes through the yoke. I think it's called the Super Duty squeezer. As I said before, if this one doesn't do the trick, then I'll get an expensive one.

When I can afford it, I'll go for a pneumatic squeezer, but that may be awhile. Thanks again for all your advise...now I'm off to the shop to start marking the rivets I need to drill and replace.
 
Honestaly, I find it easier to tip rivets with the pnuematic than my Avery Hand squeezer, so dont feel like a hand squeezer automaticaly means lesser quality rivets. Assuming everythingis mechanicaly sound and straight, its all about holding the squeezer straight. When squeezing, I like to have the smaller diameter flush set on the shop head side, makes it easier to eyeball the center of the die.
 
Update #1

For those who are interested in this rivet problem, I decided to go back and look over my entire empenage kit for bad rivets. I inspect my work right after I do it, but now that I know (better) what to look for I decided to double-check. I found several rivets on each part here and there that I've decided to drill out and replace. I just feel it's the right thing to do. I know that a rivet here or there "ain't a big deal", but oh-well...better to do it right (even if it's not the first time!).

I've also got the new rivet squeezer on the way - and I did a little checking on it's quality...it looks like it's a Tatco replica. It's identical except for the Tatco stamp on the yoke.

So, I drilled out several rivets today which is going surprisingly well. I haven't screwed up any sheet metal yet (knock on wood). I replaced the rivets by using the bucking bar and rivet gun...I don't know why I didn't do it that way in the first place...they're coming out better than the squeezed rivets that don't need to be drilled (wtf?).

Thanks again to those who replied. Onward and upward.
 
new squeezer

Just a quick update...I got the new squeezer today. It's a Tatco knockoff, but I can tell that it's 10 times better than the old one. I squeezed the rivets on the elevator trim hinge (both sides) and they came out perfectly.

I did put the 1-1/2" yoke on it before I started riveting, but I could immediately tell that there was much less flex than the old one. Thanks again for the advice.
 
I like the Tatco. The main squeeze is too big for a hand squeezer IMHO. Also don't assume everyone will buy a pnematic squeezer...
 
Rivet problem - need advice

As a Technical Counselor and a 3 peat offender, I teach riveting. I tell my students to use a rivet so that the length of the shop head side is 1 1/2 times as high as it is wide before it is squeezed and 1 1/2 times as wide as it is tall after it is squeezed. Using too long of a rivet makes it very difficult to get a good shop head. The rule of thumb I use when I do a tech inspection and look at a rivet shop head is that all sides of it should mushroom past the edge of the hole. Sometimes a poorly driven rivet can be re-squeezed to accomplish this mushrooming although it is hard to do because the rivet work hardens when it is squeezed. If you can't get all sides of the rivet mushroomed past the edge, it will probably "smoke" and should be drilled out and replaced.

Jim Cone
3 peat offender
EAA Technical Counselor and Flight Advisor
 
Wow, I learned something new today! I spent 8 years in the Navy working on airplanes and have seen many a rivet like that on F/A-18s. OK, OK I was an avionics tech...but I did spend a couple years doing A&P stuff in the phase-inspection shop.

If you don't mind me asking, Andrew, what kind of plane is that? It has the typical Navy gray paint, cherry-max rivets and those screws that you can only take out with a pizza-cutter wheel (can't remember the name of it!).

Update: - Doh! I just saw your subject header...I guess you didn't take that picture yourself. :cool:
 
Yeah I don't know what plane that is. The caption just says: "Rivet that is loose and fretting with tail"

Does anybody have experience with these on RVs? I would imagine the fretting just makes them get looser with time. Need to be drilled out and replaced when first detected or can you wait a bit? Any experts?
 
scard said:
I'll add some more chaff to this pile. I had a "Main Squeeze" when I started my project, and no matter how much I practiced and analyzed, I couldn't form a decent rivet. I quickly (after many days and hundreds of rivets of practice) abandoned the manual squeezer for a pneumatic and never looked back. The pneumatic squeezer arrived and I was immediately forming nearly perfect rivets every time. I was amazed. I never did figure out the hand squeezer and sold it.
Click to expand...

Ditto on the pneumatic squeezer. I sold mine after the project was completed and it did not cost much to own it for a couple years.
 
jamescone said:
As a Technical Counselor and a 3 peat offender, I teach riveting. I tell my students to use a rivet so that the length of the shop head side is 1 1/2 times as high as it is wide before it is squeezed and 1 1/2 times as wide as it is tall after it is squeezed. Using too long of a rivet makes it very difficult to get a good shop head. The rule of thumb I use when I do a tech inspection and look at a rivet shop head is that all sides of it should mushroom past the edge of the hole. Sometimes a poorly driven rivet can be re-squeezed to accomplish this mushrooming although it is hard to do because the rivet work hardens when it is squeezed. If you can't get all sides of the rivet mushroomed past the edge, it will probably "smoke" and should be drilled out and replaced.

Jim Cone
3 peat offender
EAA Technical Counselor and Flight Advisor
Click to expand...

Hi, Jim. Glad to hear you are alive and well......and thanks for the demo ride in the 6A a some years ago.

P.S. I attended one of Jim's rivet classes before starting the 7A project and before he moved out west. It was an excellent 2 hour session. He even cautioned about not drilling a #40 hole in a finger, which I did anyhow sometime later. :)
 
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