First frustrating day

[flyingRV]

Yesterday was my first very frustrating day.
I was looking forward to riveting the skeleton of my RV7 VS. So far everything went pretty smooth, I'm nearly ready to rivet the HS but decided to replace one part.
While waiting for delivery I started the VS and was pretty confident (after the rear spar came out nice) until I began riveting the VS-704 to VS-706 to the front spar. Not even one single rivet fit nicely. The rivets bent, the shop head was not even, there was a gap between the flanges an the spar, or the manufactured head and the metal...
I drilled out several times, fittet, fluted everything again, clecoed together, it looked good but as soon the first rivet was squeezed the same sh... happened again. Now all the ribs have marks, the holes are uneven so I guess I have to replace all of them maybe also the spar. See pics.
I have no idea where the problem is, I'm totally new to building with metal but the practice kits (I did 4 of them) came out pretty nice.

I suspect the forward and aft flanges of the ribs are not in the right angle for the shape of the HS.
How can you make sure? As soon as I put clecos in the flanges are pulled in the right position and it looks good.
Also I'm afraid the holes are not 100% perpendicular from the spar into the fwd and aft flanges.

I checked several building blogs and nobody seems to have such problems.
Now I'm afraid I'll encounter the same problems when riveting the HS.

Any ideas?

Thanks

 

[leok]

Looks to me like the gun, bucking bar, and the rivet are not all in alignment when you try to set the rivet, and/or the gun pressure is set too low. All must be in a straight line. Also setting an AN4 takes more pressure in the gun than setting an AN3. If all of your practice has been with AN3 rivets, set up a practice line of AN4s and dial in the gun for the larger rivets. Trying to set at too low of a gun pressure leaves you pounding away while everything moves around.
In the case of the ribs, it can be next to impossible to get the gun, rivet, and bucking bar all in a line. bend the flange out slightly to get clearance, rivet, then bend back. You can also reverse the rivet direction if that gives better alignment to set the rivet.

Good luck

 

[wirejock]

Clinched rivets

Yep. What he ^ said.
The bar or gun is out of alignment.
Practice. It's counter intutive but the rivet clinches in the opposite direction from what you think. It actually tilts toward the tilt of the bar almost like it's chasing it.

 

[Draker]

Also this might be obvious and you're probably already doing this but clamp everything down when using the rivet gun.

Getting far through the HS and starting on the VS, before having your first frustrating day is a great sign! My first frustrating day was sorting through the rivet bags in the Empennage kit.

 

[bjdecker]

Don't forget to debur the holes, sand/break/polish/debur the edges of everything...

You mentioned "squeezing" -- what tool are you using to set these rivets? A manual squeezer (Mainsqueeze, Tatco) or pneumatic (CP214) type?

In the case of squeezing, you need to make sure the yoke & sets start out and remain square to the rivet and workpiece. If you allow the tool to twist or rotate then you will end up clinching a rivet.

If the rib or flanges are in the way of the tool, flip the tool and the sets around (consider a longeron yoke also) to gain unimpeded access to the rivet.

 

[Bob Y]

Maybe it’s just the photo, but those rivets look pretty long to me for that thickness of material. Any chance that could be the issue?

 

[MIKE JG]

PS you're going to have a lot of frustrating days..... just keep going.

 

[scrollF4]

Maybe it’s just the photo, but those rivets look pretty long to me for that thickness of material. Any chance that could be the issue?

My thought exactly. The build schematic’s rivet callouts are usually accurate, but you can use a different length rivet as necessary. Try a rivet length one size shorter than the callout.

 

[Stevea]

first day!

First of all, congratulations on your first day of RV building. The first of many more to come.

As far as the frustrating part goes, well that does come with the territory. Hopefully you will gain experience and have many more days with better outcomes.

The top rivet (bent over) does look like it was too long to start with. When it comes to 1/8 inch rivets, I found them to be easier to bend over....although I've bent my share of 3/32 inch rivets too. If you don't have one, make or buy a rivet length gauge: https://www.aircraftspruce.com/catalog/topages/averyrivetlengthgauge.php?clickkey=9219
And, go with what the gauge says versus what the plans call out for selecting the correct rivet length. Van's does a good job of getting the rivet length call out right, but some of them do come out on the high side (at least on my -6A). After a while you will be able to look at the selected rivet in the hole and decide too long vs length ok just by looking at them......until then use the gauge.

Another hint with rivet length I found worked for me. If you have a choice between too long and too short a rivet (per the gauge or scale measurement), always take the too short option. For me, too long almost always seemed to bend, 1/32+ inch short almost never did. A rivet cutter and/or a file can be your friend here.

Also the rivets going through a two piece joint are easier to bend than the ones through a thicker stack up, probably because they can tip in the hole easier than the thick stack.

 

[Bcone1381]

Long rivets tip over like that. I echo what Steve said, finding a proper length rivet is very forgiving but almost impossible to form a proper shop head on a long rivet.

Your next concern might be that a shorter rivet has insuffiecent volume of its exposed stem to form a shop head with legal thickness and diameter. I like using the Mil-Spec rivet document and digital calipers for my guidance on whether teh rivet is good. You want the shop head diameter and thickness to conform with this document link. see table IV Steves Rivet Gage is probably the same....probably is the key word.

https://www.vansaircraft.com/wp-content/uploads/2019/02/MIL-R-47196A_MI.pdf

Lastly, some don't know that the shorter rivets have half size lengths. Like between an AN426AD3-3 and -4 is a -3.5. I love them. Cut rivets never buck right. the cutting action work hardens the stem I think.

 

[Blain]

Practice on scrap. Or buy the tool box kit. Get a good feel of setting rivets before trashing good parts. I still have my first practice scraps I riveted together. Looks just like yours.

 

[flyingRV]

Thank you so much for the tips and motivation.
I can't recall the rivet length. I have a gauge and used the size called out in the plans, but maybe I made a mistake there.
I squeezed most of the rivets with the Cleaveland manual squeezer except VS 704/705. I see no chance to get there with my yoke.
Until yesterday the squeezer worked pretty good on the practice kits. I did 4 flight control surfaces and 1 toolbox. They all came out pretty nice, even the rivets driven with the gun and bucking bar.

I tried to check all the points that you've mentioned and did the following.

1. Set up a rivet pattern on scrap material
2. matched drilled and deburrred all the holes
3. checked for proper rivet length (I have the rivet gauge from Cleaveland),
4. clamped it
5. paid extra attention to the alignment
6. and shot more than 100 rivets with the gun and manual squeezer.

In the end I was pleased with the results I think I'll do this every day now until the spare parts arrive.
Maybe it's more practice than I thought it would be.

I also looked at my messed up skeleton again and it might be that the flanges which are riveted to the spar had too much tension and were aligned only from the pressure of the clecoes. When all clecoes where installed there was no gap but as soon I removed one and inserted a rivet and was no close fit anymore.
Maybe I should also pay more attention to the proper fitting before the clecoes do the job.

Thanks again!

 

[Z-EDD]

Yesterday was my first very frustrating day.
I was looking forward to riveting the skeleton of my RV7 VS. So far everything went pretty smooth, I'm nearly ready to rivet the HS but decided to replace one part.
While waiting for delivery I started the VS and was pretty confident (after the rear spar came out nice) until I began riveting the VS-704 to VS-706 to the front spar. Not even one single rivet fit nicely. The rivets bent, the shop head was not even, there was a gap between the flanges an the spar, or the manufactured head and the metal...
I drilled out several times, fittet, fluted everything again, clecoed together, it looked good but as soon the first rivet was squeezed the same sh... happened again. Now all the ribs have marks, the holes are uneven so I guess I have to replace all of them maybe also the spar. See pics.
I have no idea where the problem is, I'm totally new to building with metal but the practice kits (I did 4 of them) came out pretty nice.

I suspect the forward and aft flanges of the ribs are not in the right angle for the shape of the HS.
How can you make sure? As soon as I put clecos in the flanges are pulled in the right position and it looks good.
Also I'm afraid the holes are not 100% perpendicular from the spar into the fwd and aft flanges.

I checked several building blogs and nobody seems to have such problems.
Now I'm afraid I'll encounter the same problems when riveting the HS.

Any ideas?

Thanks

Rest assured, this is a difficult riveting task, I remember it well almost 10 years later! The various conflicting flanges make getting a squeezer yoke in there difficult and access can still be difficult for the gun and bar.

What others are saying regarding rivet length is very valid, they do look too long and you will learn that it is still possible to get an acceptable size shop head from a slightly short rivet.

Regarding the gap between flange and spar however, this may not be a problem. The shop head has a tendency to cause the flange to bow under the pressure and it will look like that. If you take a feeler gauge (I think .002 but look it up, should be in section 5) and see if you can reach the rivet shank. If it does not reach the shank you are fine, the parts are tightly together around the rivet and the problem is purely cosmetic.

To avoid this there are some tricks, one of which is to reverse the rivet so the factory head is against the flange. If you can't get access this way there are other tricks, search "sheet separation"and you should find a few threads on this.

 

[BillL]

Yesterday was my first very frustrating day.
I was looking forward to riveting the skeleton of my RV7 VS. So far everything went pretty smooth, I'm nearly ready to rivet the HS but decided to replace one part.
While waiting for delivery I started the VS and was pretty confident (after the rear spar came out nice) until I began riveting the VS-704 to VS-706 to the front spar. Not even one single rivet fit nicely. The rivets bent, the shop head was not even, there was a gap between the flanges an the spar, or the manufactured head and the metal...
I drilled out several times, fittet, fluted everything again, clecoed together, it looked good but as soon the first rivet was squeezed the same sh... happened again. Now all the ribs have marks, the holes are uneven so I guess I have to replace all of them maybe also the spar. See pics.
I have no idea where the problem is, I'm totally new to building with metal but the practice kits (I did 4 of them) came out pretty nice.

I suspect the forward and aft flanges of the ribs are not in the right angle for the shape of the HS.
How can you make sure? As soon as I put clecos in the flanges are pulled in the right position and it looks good.
Also I'm afraid the holes are not 100% perpendicular from the spar into the fwd and aft flanges.

I checked several building blogs and nobody seems to have such problems.
Now I'm afraid I'll encounter the same problems when riveting the HS.

Any ideas?

Thanks

Inspect each rivet in your early stages of building, and if not correct, stop and figure what went wrong before botched rivets are repeated.

Looking at your shop heads, they are not bulged but tapered. This indicates that the rivet gun pressure may be too low. Practice to see the difference.

If you are using an offset set, take some baffle material, a couple of hose clamps and fasten the set to the gun body. This will keep the set from rotating and can be used one handed.

I learned that two layers of tape on the set will help avoid smiles.

Burp the rivet gun if doing this solo with one hand on each.

Have the pieces in full contact before the rivet process.

Practice using the off set driver off the actual part to get used to it. I hold it tighter on the rivet head to ensure no bounce.

 

[Draker]

Not sure if this is related but: One thing I wish I did earlier in my build was get more comfortable with the rivet gun and bucking bar. I had a nice easy pneumatic squeezer, and my attitude was "I'll squeeze everything I possibly can, and only pick up the scary rivet gun if I absolutely have to!" I was always worried I was just not that skilled with the rivet gun, so I didn't use it much, which led to me not having a lot of practice with it, which then guaranteed I wouldn't be skilled with it. It wasn't until I was halfway through the wings where you kind of have to buck everything, when I finally got comfortable with the rivet gun and learned how to feather it, use different bars and so on. It really helps the build to be able to use all the tools in your toolbox (trust me, the Vans build eventually used every single tool I had plus $hundreds of other tools.

 

[jrs14855]

Rivets

Maybe it’s just the photo, but those rivets look pretty long to me for that thickness of material. Any chance that could be the issue?

plus one on look too long

 

[jrs14855]

Riveting

If you are riveting with a rivet gun try this: create a modified bucking bar with a slightly oversize hole and countersink the hole. With a standard bucking bar buck the rivet just slightly. The goal is to set the rivet just enough to "swell" the rivet in the hole. Now with the modified bar in place tap the gun just enough to draw the two pieces together if there is a slight gap between parts. Now finish rivet. I have seen sheet metal experts do this with standard bucking bars held along side the rivet but I prefer the "custom" bar. A VERY light touch on the gun for the first two steps.

 

[BillL]

I learned something here . . . .

If you are riveting with a rivet gun try this: create a modified bucking bar with a slightly oversize hole and countersink the hole. With a standard bucking bar buck the rivet just slightly. The goal is to set the rivet just enough to "swell" the rivet in the hole. Now with the modified bar in place tap the gun just enough to draw the two pieces together if there is a slight gap between parts. Now finish rivet. I have seen sheet metal experts do this with standard bucking bars held along side the rivet but I prefer the "custom" bar. A VERY light touch on the gun for the first two steps.

Nice technique!! Thanks !!

 

[Skip12]

Bent Over Rivet

Double check the rivet length. Don't go with the length in the plans, if they aren't correct. Measure them.
PM.pnghttps://www.vansairforce.net/community/attachment.php?attachmentid=35304&stc=1&d=1671216755

 

[rapid_ascent]

That rivet looks too long. Maybe it is the pic, but its a good idea to buy a rivet gauge if you don't have one already. Once you have a lot of experience you won't need it as much but I still use mine all the time. Sometimes I've found that a slightly longer or slightly shorter rivet is the best choice versus what is actually called out in the drawings. Ideally the exposed length of the rivet should be 1.5 x the rivet diameter. Like I said with more practice you'll be able to tell this by looking at the exposed rivet. A rivet that is too long will have a tendency to bend over like your picture shows. A rivet that is too short will not have enough material to form a proper head.