You live and learn...

I am at the stage of riveting together the wing skeleton and I screwed up around 15 rivets on the main spar to rib joints across both wings on my slow build RV-9. They were all sorts of broken -bent over, elongated, ovalled, figure of eight and a good few were cracked diagonally down the shank but no smilies!

So, just when I thought I'd got the hang of this riveting lark having done all of it solo so far with no big issues, I was downhearted to say the least. I called in the cavalry in the shape of my LAA inspector (in the UK he signs off on your build, so he's your main go-to guy). We looked at the rivet length called out in the plans, which was a little on the long side of perfect but far from being an issue.

Then he asked what I'd used to drive them and bingo! I had used a double offset set because I didn't want to mark the ribs or bend them out of the way to use a straight set. We drilled them out (about 15 of them!) and using a straight set riveted in the replacements -all perfect first time. I've done some more solo since then and they too came out great.

I'm not saying a double offset set is a bad thing, just documenting my experience here in case someone else is stood looking at the same crappy rivets wondering what they've done wrong. As my inspector said: "I only use an offset set if I absolutely have to and try not to do it single-handed". When I build my next RV I'll get a longer straight set

Hope this helps someone.

Matt.
Slow build RV-9 wings
South Yorkshire, UK.

The double offset requires a lot more air pressure on the gun. Shorter sets require less pressure than long sets. More mass to move with the longer sets.

Now that the build is done, I can honestly say THE one tool I'd like to melt into molten steel, is the double offset rivet set.

Something to try.....

.........use duct tape to keep the set from spinning in the gun. Along with a little rivet tape over the end of the set. If that doesn't work, turn up air pressure, place against temple and pull trigger.
Flyinmonque

I agree with my friend Bruce, you can get excellent results from this rivet set if you listen to the details of how he uses it. There's a lot more mass involved than with ordinary-sized rivet sets, so you have to turn the air pressure way up. I turned it up as high as 90 psi, compared to the 34 - 38 psi normally used for 3/32" rivets. For 1/8" rivets, it would be even higher. If you have someone helping you buck the rivets, you can use one hand to hold the set so it won't rotate on you, and keep it in place where you want it.

I have lots more discussion and pics here:

Riveting with a Double-offset Backriveting Set

I'd do it this way again in a heartbeat. Here's how my first wing turned out:

First of all I would not claim to be an expert on this by any means. I ordered both a double offset set and a longer set for this very operation. I decided to use the longer set. I didn't like how it was going with the double offset set.

The longer set seemed to work fine. I taped the rivet gun with painters tape. I also put a couple of pieces of tape on the rib and I think I got acceptable results. I moved the rib tape from rib to rib as I went.

I wouldn't say this operation is easy. I think it is one of the more difficult operations for a new builder since we don't have that much experience using the rivet gun. I ended up drilling out many rivets, but eventually I think I got it. I did have to turn the pressure up like others have suggested. I did the entire spar by myself so it can be done. If you can get someone to help its probably much easier.

The one word of advice I would give is if you start having trouble take a break and do something else. When you get frustrated it seems to go downhill fast.

Many of those rivets came out OK and I did have the pressure up quite high - about 80psi if I remember correctly so it's a matter of my skill or lack of it. I didn't tape the set in place either and it did like to spin around on me.

I think I'd opt for a longer straight set than I currently have if I was doing it again.

The most difficult job so far has been to buck the upper and lowermost rivets on the 3 nut plates between the first and second ribs on each spar web. I had to take a rivet set to the grinder to get at those. Like so many things in this hobby of ours, it's a matter of having the right tools or making them.

Thanks guys.

Matt.

Have you tried knitting......