Main spar riveting

[Concorde]

Hi,
Time to rivet the spar and need your opinion.
1- When looking at some of the builder logs , I have noticed some builders only cleco every 10 holes at the rib attachment holes and fill all the rest of holes with rivets and cover them all with tapes. This would make it a lot easier and much faster,but is it enough ? I am thinking about putting a cleco in every 3rd hole and that brings me to my next question.
2- when placing the bucking bar under the rivets it would cover 2 rivets and while I'm driving one rivet ,what would the bucking bar do to the other rivet ?
3- when installing the SNX-W11-11, plan is giving us an option of either using AN470 rivets or the AN3 bolts as substitute,looking for recommendations.
Thank you very much.
Ben

[lstinthot]

We did significantly more cleaco's. Started out in every other hole and put the bucking bar between the cleaco's. We used a bucking bar that is about 1 inch wide for most of the rivets on the first spar. Worked with the wife on some of the rivets and we used the Sonex bucking bar, a bit heavier than our 1" wide one. It worked fine as well. Could not have as many cleaco's in using the Sonex bucking bar. I like more cleacos over less. As long as the bucking bar can fit.

I did not have an issue having the bucking bar over more than one rivet at a time. It was never over two rivets that where not set yet. Only one new rivet at a time under the bucking bar.

Sometimes we had to get creative, use another rivet gun with the shop head rivet tool on it, then back rivet the rivet due to not being able to get any bucking bar in the area.

We used rivets for the optional AN3 bolt area. Could not see any benefit to using bolts. If the rivets are strong enough, I do not see myself taking the part off or wanting to check the bolts during inspections.

[Concorde]

We did significantly more cleaco's. Started out in every other hole and put the bucking bar between the cleaco's. We used a bucking bar that is about 1 inch wide for most of the rivets on the first spar. Worked with the wife on some of the rivets and we used the Sonex bucking bar, a bit heavier than our 1" wide one. It worked fine as well. Could not have as many cleaco's in using the Sonex bucking bar. I like more cleacos over less. As long as the bucking bar can fit.

I did not have an issue having the bucking bar over more than one rivet at a time. It was never over two rivets that where not set yet. Only one new rivet at a time under the bucking bar.

Sometimes we had to get creative, use another rivet gun with the shop head rivet tool on it, then back rivet the rivet due to not being able to get any bucking bar in the area.

We used rivets for the optional AN3 bolt area. Could not see any benefit to using bolts. If the rivets are strong enough, I do not see myself taking the part off or wanting to check the bolts during inspections.

I only have the sonex bucking bar,so putting cleco in every other hole wouldn't work.
The problem that I am having right now on my practice pieces is,after I set a few of the rivets and then remove the clecoes,the holes are too tight for rivets to go in,what's the best way to deal with this ?
I'm doing this solo,what I think is that I'm not holding the bolt straight and causing the parts to move on each other.
Thanks for your help.

[Bryan Cotton]

Ben,
I bought my spars prebuilt but I scratch built a hummelbird including the spars. Here are my recommendations:

1) every third cleco is fine. Remove whatever cleco you need to when setting a rivet.
2) Don't just rivet down sequentially. That will give you the maximum creep of the web against the caps and the greatest bananna effect. Shoot a couple in the middle, then the ends, then halfway between and so on. Once 10-20% of your rivets are set then do whatever. Also, that creep is what makes the rivets tight to insert.
3) If I can't get a rivet in I use a hole alignment tool. It is also known as a drill with a #21 bit for the AN470AD5 rivets in this case. You should only be taking off a couple thou and the rivet will happily take up that space.
4) Whenever I have a choice between an AN3 bolt and a rivet I remember that weight is the enemy. Rivets are lighter!

[Concorde]

Hi Bryan,
Which would be better,using the #21 bit to enlarge the holes or tap the rivets in if I can ?
Thanks

[Bryan Cotton]

Ben,
If you can push them in that is ok. If you have to tap them in they may get stuck partway down. I've done both and I go for the hole alignment tool as my preference.

[lstinthot]

I would check with your local EAA chapter to see if they have a rivet squeezer. One here did, it just happen to be not working when we were ready to rivet. It will take a pretty good size squeezer to do the *5 rivets. I did some of the rivets by myself, can be done just not as nice a finish compared to the ones I had help with. We did use the technique to move around the spar, not on purpose, it just worked out that way. With every other rivet hole, I have very little banana effect. We did have a few counter sunk rivet holes that I chased with a drill bit. Did not have to actually turn the drill bit with the drill, just work it through the hole was all that was needed. An RV builder showed me that. You will need some kind of other bucking bar to get under the upper stiffener angle W11-08 and the spar cap. Might be a scratch building thing, but my gap between the spar cap and the stiffener is to tight for a rivet tool to fit in there and I had to come up with a piece of metal about 1/2" thick an inch or two wide to act as a bucking bar.

Mike

[Concorde]

I would check with your local EAA chapter to see if they have a rivet squeezer. One here did, it just happen to be not working when we were ready to rivet. It will take a pretty good size squeezer to do the *5 rivets. I did some of the rivets by myself, can be done just not as nice a finish compared to the ones I had help with. We did use the technique to move around the spar, not on purpose, it just worked out that way. With every other rivet hole, I have very little banana effect. We did have a few counter sunk rivet holes that I chased with a drill bit. Did not have to actually turn the drill bit with the drill, just work it through the hole was all that was needed. An RV builder showed me that. You will need some kind of other bucking bar to get under the upper stiffener angle W11-08 and the spar cap. Might be a scratch building thing, but my gap between the spar cap and the stiffener is to tight for a rivet tool to fit in there and I had to come up with a piece of metal about 1/2" thick an inch or two wide to act as a bucking bar.

Mike

Hi Mike,
I have to check on that, but I think the Sonex bucking bar would fit under the spar cap with no issue.
Thanks