HS-710 / 714 countersunk rivets. HOW?

I messed up the four counter sunk rivets in the middle of the HS-710 and 714 spar. I was riveting just fine, then forgot that I needed countersunk in those two holes. Fortunately, I just had two rivets to remove. Cleaned up that mess and tried again with the correct ones now.

This time all 4 of them bent over! I was using the rivet gun on the shop side, while holding the buck bar on the countersunk side. What the heck am I doing wrong? All 4 were messed up so I had to remove them all. Now I've spent the last hour reading builder sites to see if anyone has the same problem. No.

Here is what they look like -


And the other side:


The holes did get very slightly bigger during removal, but I think they will fill in once I mash the rivet down again. As long as I don't mess up again and have to remove them on e more time. So any adivce on these things? I'm only about 25 rivets into this project and have already removed about 6, my good rivet ratio sucks so far! I do have a pnuematic squeezer also, but not sure if it fits nicely around that flange. I'll have to test fit that.

The 4-6 rivet seems to be the correct lenght according to the gauge too.

Any ideas for a RV7 riveting newb?

Thanks.

Tom

tegwilym said:

This time all 4 of them bent over! I was using the rivet gun on the shop side, while holding the buck bar on the countersunk side.

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I think you just answered your own question. I fold over a lot of rivet heads when I try doing that. I have learned to always keep the bucking bar on the shop head side, if at all possible.

tegwilym said:

The holes did get very slightly bigger during removal, but I think they will fill in once I mash the rivet down again. As long as I don't mess up again and have to remove them on e more time. So any adivce on these things? I'm only about 25 rivets into this project and have already removed about 6, my good rivet ratio sucks so far! I do have a pnuematic squeezer also, but not sure if it fits nicely around that flange. I'll have to test fit that.

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Hang in there, it gets better as you gain experience. Sometimes too slowly to save you, but it's almost always fixable. You'll also get better at drilling them out. I haven't had to use an "oops rivet" in a while now. Oh, and... word of advice... that pneumatic squeezer is really handy, but it will also let you make bigger mistakes, faster.

Hmmm... So I just need to reverse my methods?
Hammer the countersink and buck the shop side instead? I did that way with the round head rivets on the rest of the HS-710/714 spars. It all went very well. I guess I'll give that a try - after a test run on my Boeing scrap piece!
Thanks for the reply! Lately this is my favorite web site.

Tom

bucking bar

I check to see if I can use the squeezer every time.
If not then I go for the titanium bucking bar.
if that is won't fit I start cussing.

We have some good, fancy tungsten bars.
I've cussed at some point in every part of this project. By the time I'm done though, I'll be a expert plane builder...or a sailor!

+1 for the tungsten bucking bar .. It fits easily in all sorts of places, ESP when you are putting on the HS skins. A squeezer works great here. I love my alligator (hence my avatar).

Before I knew about oops rivets, I messed up one of the HS skin rivets so bad multiple times that I just put a 4 in and drove it home. Hardly can tell now!

I count my tungsten bar as one of the very best tool purchases I've made. I use it ALL the time. I had to use the steel one today to get at some stuff I just couldn't reach with the little tungsten bar, and it was the first time in a couple of months I'd taken it out of the case.

When I riveted the top skins on the left wing, I had my son on the outside with the bar, and I was on the inside with a double-offset back riveting set. The flush heads on the outside look great. The shop heads... well... the airplane will fly, but it's not my finest work, let's put it that way. We're doing the right wing now; I showed my wife how to use the rivet gun and I'm on the inside with the tungsten bar. Much better. I got a big mushroom set with the rubber ring, and both ends of the rivets are coming out great.

Yep. We also have the red rubber mushroom attachment also. I think that is the one I'll try now and hopefully get through my latest dilemma - or should I say "learning experience!"

UPDATE: I just tried it with the tungten and the shop side and the riveter with the red rubber mushroom over the riveting tape and the factory end. Worked ---- Perfectly!

Got the heads mushed down just past the gauge radius, and just slightly higher than the cutout. Perfect fit and it's not smeared over the side like I did before.

THANK YOU!!!!! I owe you guys a beer, latte, bottle of wine or a ride in the plane in 2 years.

One more quick question: how hard do you need to push the bucking bar while riveting the other side? I may be pushing it too hard, but then it's a massive little thing so maybe I don't need that much pressure.

Thank again!

Tom

Tom,
You want to keep enough pressure on the bucking bar so that it doesn't bounce off and on the rivet. You don't want the gun hitting the rivet head while the bar is not in contact on the shop end, if you do the gun is driving the skin/structure instead of the rivet. Like everyone else, I love the tungsten bar as well, I have it doubly good because I am using my friend Steve's bar while he works on his canopy, so didn't have to shell out the big bucks (yet).

The absolute KEY is keeping straight on the rivet. If you push ANY amount off the centerline of the rivet it will bend over. That's why a squeezer is best because you can see and control the geometry before & during the squeeze. Once you start hammering with the gun, that bucking bar can go any which-way if you aren't extremely careful. The gun AND the bucking bar have to be pushing very firmly on the rivet AND the head must be fully seated, then about 3-4 raps of the gun and presto, done.

It's "EZ", but you have to be in control of the geometry.

Glad it all worked out. There is a technique to removing rivets that does not enlarge the hole - this would be a great skill to practice and master with the scrap pieces you mentioned.

When drilling out a rivet, do not drill all the way through it. Instead, start drilling on the manufactured head side, just deep enough to drill all the way through the rivet head and not the shank. Remove the drill and use the blunt end of the drill bit to pry/snap the head off. Then use a punch nearly the size of the hole, with a hammer, to knock the rest of the rivet out. Done properly the hole will not suffer any enlargement.

If a hole does become slightly enlarged, sometimes pre-squeezing a rivet just a tiny bit to make it fatter can help keep the shop head from folding over.

Finally, as you discovered here, drive from the manufactured head side whenever possible, and buck the shop head. No need to smash the bucking bar against the rivet when driving - the rivet gun will do the work. Just keep the bucking bar steady on the shop head side and all will be well.

Everyone struggles at the beginning - you're doing great. Keep at it and practice a lot. Ask lots of questions.

Drilling out rivets ...tip that helped me out.

Ditto to what the previous poster said on drilling out rivets. A great tool that I have that makes taking bad rivets out a breeze, is a spring loaded centre punch.... I think that's what you call it anyways. Get the smallest one you can find for the best results. I got mine from Busy Bee Tools in Ottawa, Canada.

You drill into the head of the rivet very carefully, so as not to be drilling the edge of the hole, almost to the point where the stem is being drilled. Be exactly centred with the drill bit, and take it slowly. I even use Beolube on the bit. The rivet will still be firmly in place, but the head will be weakened so that the punch will take it out.

This spring loaded centre punch just works by applying hand pressure to it. It stores up spring pressure, then snap, it kicks as if it has been hit by a hammer.

Remember to back up your work with a bucking bar next to the shop head (but not covering the shop head), so that the jolt doesn't damage the material that you are removing the rivet from. If the head breaks off, and the stem gets kicked out, then you are in business, and the hole has not been enlarged. If the head doesn't break off, then drill very slightly deeper and try the punch and bucking bar again.

I'm sure there must be some online how-to videos on you tube or through through the EAA that will help you out with your technique, both for riveting , and rivet removal.

Happy building,


Steve Wolfe

Go as slow as you can with pneumatic squeezer and keep straight. Slow slow slow! I had a similar issue. If the pneumatic reaches use it.

modified bar

Sooner or later you find a spot where only that little steel bar will fit. For those times, I tape my tungsten bar to the steel one to give it some mass. I also use small strips of gorilla tape on the edges of whichever bar is used to prevent marring of the web or flange area. Gorilla tape rates up there with Boelube.

wirejock said:

Sooner or later you find a spot where only that little steel bar will fit. For those times, I tape my tungsten bar to the steel one to give it some mass. I also use small strips of gorilla tape on the edges of whichever bar is used to prevent marring of the web or flange area. Gorilla tape rates up there with Boelube.

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HUM.....would that be the deck plates on the fuse....

tight spot

Not yet for me but thanks for the warning.

tegwilym said:

We have some good, fancy tungsten bars.
I've cussed at some point in every part of this project. By the time I'm done though, I'll be a expert plane builder...or a sailor!

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Dude. Get used to it during every "section" of the build you will be facing a arch nemesis. Make him your freind & learn from him... proceed slowly & take your time Think before doing... follow the order in the plans. I just spent $70 buck in shipping to replace $30 worth of part... dumb me had this grand idea of drilling the aileron counterweight prior to clecoing the LE to the aileron skeleton. the holes curled around the counter weight tube & I had a nice twist in the aileron leading edge... dumb me!

Daniel S. said:

Dude. Get used to it during every "section" of the build you will be facing a arch nemesis. Make him your freind & learn from him... proceed slowly & take your time Think before doing... follow the order in the plans. I just spent $70 buck in shipping to replace $30 worth of part... dumb me had this grand idea of drilling the aileron counterweight prior to clecoing the LE to the aileron skeleton. the holes curled around the counter weight tube & I had a nice twist in the aileron leading edge... dumb me!

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You got that right!
I'm finally calling myself a riveter after screwing up a bunch of them. I can now remove them is many cases, in about 5 minutes or less. Learning from mistakes and moving onward!