VAF Forums

VAF Forums (https://vansairforce.net/community/index.php)
-   RV General Discussion/News (https://vansairforce.net/community/forumdisplay.php?f=2)
-   -   Why do my rivets suck? (https://vansairforce.net/community/showthread.php?t=125160)

s10sakota 04-28-2015 07:48 AM

Why do my rivets suck?
 
I am so frustrated right now I'd like to beat this airplane with a sledge hammer!!

I'm trying to rivet the seat pan ribs and baggage compartment ribs to the aft spar. I can't figure out why my rivets are folding over.

In one hole, the rivet cracked and broke right as I started squeezing it. They are very difficult to drill out because the head is on the inside of a rib. I drilled it out, put another rivet in, and it folded over. Drilled that rivet out, made such a mess of the hole, that I had to put a bolt in it.

Now I have two others that folded over and I have to figure out how to drill them out without messing up the holes.

Here's one...



Same one...



And look at this one-it's folded and maybe cracked.



I am squeezing these with a high quality squeezer. I'm trying to keep everything square and the squeezer 90 degrees to the surface.

So why are these dang rivets folding? I'm using the proper rivets per the plans, and they don't appear to be too long. Should I use shorter ones anyway?

What am I doing wrong??? Why does no one else have any of these issues? Every blog I read they all say "riveted the ribs in. Pretty easy...no problems, etc..." :mad:

Sid Lambert 04-28-2015 07:58 AM

When the head bends over and the rivet is the correct length that simply means the squeezer wasn't straight.

If I use a very long yoke on my Tatco I notice it bends and can cause this, especially on -4 rivets.

Raymo 04-28-2015 08:00 AM

I'd get out the 3x gun and tungsten bucking bar and see how it goes the old fashioned way.

DaleB 04-28-2015 08:09 AM

Those rivets are a real challenge to set right. I ended up drilling out about a dozen of them, and even that is a challenge because of the angles involved. I ended up having to use an electric drill and a 12" bit to get them out. I finally got everything together, in good shape and done to standards, but I will be the first to admit it's not my finest looking work and there may have been some judicious use of profanity involved at some point.

I had no luck at all with a squeezer, had to set them with a gun & bucking bar. And of course the gun was a challenge (as you well know by now) because of the tight quarters. I believe I used a double-offset for most of them, taped to the gun, and it took some contortion.

It might help to get an experienced riveting partner. Especially helpful would be someone who has built an RV before and knows what you're up against.

Sid Lambert 04-28-2015 08:14 AM

Another tip is to make sure whatever you're working on is stationary. Clamped down in this case.

s10sakota 04-28-2015 08:28 AM

I'm thinking of just wrapping everything really good with duct tape. That should work, right?

Seriously, thanks for the replies. I think I'll just wait now until I can sucker a riveting partner here to help.

(the ones I did drill out, I did use a 12" bit. But naturally, the bit wandered because of the angles involved and drilled the head completely off center...)

wirejock 04-28-2015 08:49 AM

Idea
 
I am heading to the same place in a few days.
I know the manual says to start at the 704 bulkhead but...
Is there any reason why these can't be set before the seat ribs are set to the 704 aft bulkhead?
That would allow both ribs to flex out of the way a little.

bret 04-28-2015 10:02 AM

I DO remember those to be a pain to set! I dont know why....

Sig600 04-28-2015 02:12 PM

Is it a pneumatic squeezer? Make sure you're not just smashing them if it is. Feather the trigger just enough to where it closes on the rivet, then Depress the trigger until it sets the rivet. Adjust air pressure as needed and make sure you're using the right size dies.

sahrens 04-28-2015 08:35 PM

Rivet length
 
Working from the first photo, the top rivet looks a little long. Double check to make sure you have the correct length. Could just be the angle of the photo but it they are too long it is much easier to bend the rivet. It the distance needed is less than the call out, cut the longer rivet down. Or order some half sizes like 426-3-4.5

Sometimes a pneumatic squeezer yoke will fit well enough to get over the rivet, but when you squeeze the rivet the yoke will hang up on a flange. This will change the angle of the set just enough to damage the rivet.

There is enough difficulty getting an offset rivet gun on these you might want to get a bucking partner. That way you can concentrate on keeping the rivet gun over the head while someone else manages the tail. It lowers the frustration level a lot. My wife is a much better riveter than I am.

Also on over sized holes there are larger rivets than 426-4. If you have edge distance for an AN-3 bolt you have edge distance for an 426-5 rivet so you might consider those. I struggled with those ribs as well. I was glad when I finished that work.


All times are GMT -6. The time now is 03:10 AM.