Riveting is my issue

MarcoAviator · #1 05-08-2006, 08:47 AM

OK ... so I went to Greg Piney's "laboratory" on Saturday (thanks Greg!) and practiced on building the Van's Box. That was the starting step I imposed on myself before making the final decision and actually purchase the empannage (well ... the next step is setting up a shop and that alone might take months!).

I filed, drilled, dimpled, deburred (the holes) and did other funky stuff I have never done before in my life and I don't think I had any problem whatsoever doing any of these things. They weren't hard to do ... and they weren't boring (granted it's only the box, not 20 feet worth of wing ... the story might be different on more than a couple of inches of metal box and by hole 9,999 I might get sick of it).

But still ... I sort of fell into a trance while doing all these "repetitive" tasks. I wasn't bored and I felt I could do them for hours at an end without getting tired. I can totally see myself spending a full 8 hours in the shop and getting out only when my wife knocks me over the head with a baseball bat and drags me unconcious to the dinner table to be force-fed with a funnel ...

I am actually having a very positive outlook on the whole experience. I am very glad I did this as a trial and I am optimistic that I can actually do this.

The only problem came down to be ... riveting.

Somehow I am having some trouble keeping that gun steady. I don't rivet enough: the rivets are sorta "half" planted ... not fully "squished" (is there a technical term I am looking for here?).

The guns bucks and rolls in my hands and I kinda strayed all over the place with it a couple of times. The metal was not damaged (I expected the gun to rip the metal apart if it went off the rivet but it didn't).

On the other hand some rivets came out ok some others didn't come out ok at all.

Maybe I am missing something but I was having a real hard time keeping the gun still while in operation. And that was just operating the gun.

I didn't actually operate the bucking bar which (according to Greg) requires more concentration than the operating the gun.

That's bad news for me because I feel that I screwed up 50% of the rivets and of the other 50% only 2 or 3 were actually acceptable (we must have done about 18 or so of them in total).

I am worried about this because if I have 10,000+ rivets to put in the wings, and I have such a bad percentage ... this might prove impractical for me.

Is it normal to screw up rivets?

Does it get better with practice (I bet it does but then I might have to practice some more ... maybe I need to buy another box and try to build that on my own)?

Is there a percentage of screwed up rivets that is unavoidable even with the best of riveters?

How much is it acceptable to screw them up?

How much have you guys screwed them up? Or is it that after 20-30 rivets you don't screw up anymore and you just get the hang of it?

These are all questions that are running in my mind right now.

The other thing is that riveting is hard enough if you have 2 guys working on it on their own time but ... if you don't have that, if you are alone, then I get the impression this is a lot harder and I was already having a lot of trouble as it is.

I enjoyed the process. I am confident that if I start, I will be able to finish ... I just need to win over this problem I have with riveting.

LettersFromFlyoverCountry · #2 05-08-2006, 08:54 AM

Quote:

Originally Posted by MarcoAviator

Somehow I am having some trouble keeping that gun steady. I don't rivet enough: the rivets are sorta "half" planted ... not fully "squished" (is there a technical term I am looking for here?).

The guns bucks and rolls in my hands and I kinda strayed all over the place with it a couple of times. The metal was not damaged (I expected the gun to rip the metal apart if it went off the rivet but it didn't).

Do two things and you'll be fine:

(1) The tendency is to push back with the bucking bar. Don't do this. Keep it on the work, but don't push back hard with it. Let it do the work. Hold the bucking bar in your palm (or at least halfway down your fingers) and hold your fingers on the piece itself. If the manufactured head is protruding above the work, you basically pushed it out with your bucking bar. Bad thing.

(2) ... if things are bouncing around, you probably have the pressure on the gun up too high. The tendency for newbies -- and me too until I was working on the fuselage -- is to want to BLAST your way to the perfect rivet. Turn the gun down. And you might even try shorter bursts....blrp...blrp...blrp .... instead of one long blrrrrrrrrrrppppppppppppp."

(3) If you do nothing else...when you release the trigger on your rivet gun...cont..."one throusand one...one throusand two" and THEN take your gun off the work.

You'll get it.

Jamie · #3 05-08-2006, 08:58 AM

What type of rivet gun are you using?

Here's a couple of hints:

I'm using an ATS 3x gun and love it. I started with a 2x and it just didn't cut it on the 1/8 inch rivets on the wing spar webs.

* Make sure you're using a high quality swivel regulator at the rivet gun.
* I put my line pressure at 70psi.

If your gun is jumping around too much, it sounds like you're using too much pressure or the pressure isn't smooth (hence the need for high pressure and the swivel regulator).

I wasn't happy with the swivel regulator I bought from Cleaveland because it completely opened and closed in about a half turn. The one I bought at ATS was much better, IMHO and allows you to get a much more precise pressure in the gun. Always try your pressure first against your workbench. You should be able to control the gun one-handed before you start banging on metal.

Swivel Regulator

Hope that helps,

MarcoAviator · #4 05-08-2006, 09:07 AM

Thank you.

I understood half of the things you guys said ... which is GOOD because it means that I am missing something. Didn't know you could regulate pressure on the gun ... don't know what a swivel regulator is and I assumed you needed to keep the guns steady with both hands ...

The thought that you can keep the gun in one hand and the bucking bar with the other and still successfully squish one of those dreadful little buggers properly in place seems interesting. I am sure it's possible because I have heard of people being able to rivet solo ...

Obviously I need to look into all these things you guys mentioned.

Definetly I need to be able to do this precisely before I start banging at precious wing or stabilizer skin ...

Thank you!

PS: No clue whatsoever what type of gun I was using ...

mdredmond · #5 05-08-2006, 09:31 AM

FYI Brown Tool has that swivel for five bucks cheaper: Brown Tool

jcoloccia · #6 05-08-2006, 09:58 AM

Rivetting gets better with time. When I first started, I must have gone through 30 -4 rivets on a scrap piece until I got my first one to set right. Then I did a lot of practice with Ellen.

Fast forward a year, Ellen can shoot flush rivets and buck the -4's like a pro (it's easier for her to buck than to shoot the -4's), and driving rivets is just not a big deal for me anymore.

There are lots of tips out there. My favorite is a little piece of masking tape on the universal rivet set...really seems to help keep everything centered, especially when you're holding the gun at an awkward angle with the offset sets.

By the time you're done with your empennage, you'll be left wondering what all the fuss was about.

Bob Axsom · #7 05-08-2006, 10:11 AM

There are some rivets in locations that are extremely difficult to set. You will require special bucking bars to complete the job just to to get the bucking bar on them. Your posts in the forum in this thread reflect a total novice appreciation of the technology. No one is going to post messages here and make the need for you to aquire the skill go away - there is some art involved in riveting and you need your own personal talent. I disagree with the previous post that implied it is OK to hold the bucking bar lightly against the tail of the rivet but the rivet set in the gun has to hold the rivet hard in completely installed position and the bucking bar has to be firmly in position against the tail of the rivet - no force - no deformation and creation of the shop head. Rivets will work harden with repeated hits and the rule of thumb is three attemps to get the final set before replacement. A regulator is a little device that screws into the air inlet port of the rivet gun that allows you to adjust the pressure in the gun with usually with a few test hits on your work bench or a test rivet strip. Your intuitive view that you may need more practice is correct you also need to develop the critical attitude that this is a deadly serious process and you do need to develop some expertise.

Bob Axsom

jchang10 · #8 05-08-2006, 10:44 AM

I am done with my empennage and waiting for my wing kit, so these are my riveting lessons learned...

I definitely agree that practice makes "better" if not quite perfect. For instance, I have bucked far more 426 3-3.5 rivets than most others. I am quite proficient at these rivets. I have found that my 3x gun needs to be at quite a low pressure (i keep forgetting to measure the PSI at the gun). However, it is set so that at full trigger, bam bam bam bam, and the rivet is set.

For 1/8 rivets, though, the same pressure setting above does hardly anything to the rivet. I have to up the pressure a specific amount to start having effect on the rivet. I have not practiced 1/8 rivets enough yet to have developed a steady tempo to set a rivet in one go.

However, the above only holds true if the gun and bucking bar can be held horizontally to each other - the most natural position.

I just riveted the aft deck piece on the tailcone, where I had to drive the rivet straight down. In this, less natural position, the same techniques used above proved inadequate and left me with a shallow divet - too much pressure on the gun. My mistake was not adjusting the pressure or counteracting the pressure by applying enough opposite pressure on the bucking bar, to counteract the 1G down force of gravity itself. Another Homer DUHHH moment!

The lesson of my experience is to practice until you've discovered your own personal best settings. However, adjust those golden settings for varying positions you will have to use to shoot a rivet.

Jae

alpinelakespilot2000 · #9 05-08-2006, 12:36 PM

Just keep practicing, marco. You'll get the hang of it soonner or later. There will always be problem rivets and rivets that are difficult to squeeze or buck because of where they are at, but riveting really isn't rocket science. I'd second Bob Collin's recommendation not to try to push too hard with the bucking bar... just enough pressure to let the weight of the bucking bar do the work.

Also, since you're probably (and naturally) stressed about it now, rest assured... even poorly set rivets (within reason) are very strong. I think if you look in section 5 of your newer assembly manual, you see Van's has included the report that says something like even poorly set rivets (again, within reason) are something like 95% as strong as a perfectly set one.
Note that I'm not encouraging sloppiness: Always strive to set them as best you can, but recognize that a few dingers are going to end up in your plane. That's why Van's has so many more rivets than are necessary.

Good luck. You'll be enjoying building soon enough. It's not all frustration!

LettersFromFlyoverCountry · #10 05-08-2006, 01:01 PM

I don't think we found out what rivets you were setting. Jamie said he sets the gun at 70 psi. I assume he's talking about setting "4"s because that'll blow the brains out of the 3's.

I've seen various pressures posted. You'll want to try your own. And it also changes depending on the length of the rivet. But for , let's say, a 3-3.5 flush head rivet, I usually run the gun at about 38 psi. For a 4-5 universal head (round), about 62 does it for me.

Others have different psi that work for them.

If you haven't read Dan Checkoway's treatise on this, then you must. Next to Macbeth, it's the greatest piece ever written.

One other thing that's really important. Most of us have had to learn how to do this. There aren't a lot of folks who were professional riveters when they started this project and while there are plenty of folks out there who seem like life-long experts, most of us were in that position once too.

Remember the goal of experimental aviation: recreation AND education. This is the education part.

It gets better.

Just remember to pass along everything you learn to the next guy.