Rivet help

So working on the wing ribs to spars. In retrospect I should have started with the main spar before riveting the rear spar.

I'm have problems riveting the ribs to the main spar. I'm using my offset shank and applying some pressure to the rib web to get straight as possible on the rivet head. However i'm still creating divots in the rib flange. As well as causing some pillowing between the holes.

I know typically the shop head should be on the thicker material, but in this case I think the damage this causes is worse than flipping the rivete around.

For the right wing, I will do main spar first so I can slightly push the rib back to be square.

Any thoughts?

Looks Like An Awful Lot of Hammering

If you have to hammer that much to set a rivet, the problem may be in the lack of mass of the bucking bar. Try a much heavier bar. It shouldn't take more than a few pulses to properly form a shop head and the process shouldn't leave the factory head looking "hammered". I had the same experience.
Terry, CFI
RV9A N323TP

terrykohler said:

If you have to hammer that much to set a rivet, the problem may be in the lack of mass of the bucking bar. Try a much heavier bar. It shouldn't take more than a few pulses to properly form a shop head and the process shouldn't leave the factory head looking "hammered". I had the same experience.
Terry, CFI
RV9A N323TP

Click to expand...

I agree I can use my larger bucking bar. I still think the divots, or smileys in the flange will happen due to not being fully square on the factory head.

It's hard to see in the photo but the divots are on the left side next to the head.

This may or may not help, if you can't get the set square on the head, but...try putting some masking tape or duct tape on the set. I found it kept it the set from moving around, and I ended up with MUCH better-looking rivets when I did that. In most cases, the rivet factory heads came out looking as if they'd never been touched.

Using one hand to hold the long, offset rivet set collar right at the rivet helps, too, otherwise it will tend to spin and slide off the head. You'll need a bucking partner, obviously, to do this...

Tried bigger bucking bar, adjusting psi, and using two people. The factory head looks better but I'm still not able to get square on the head resulting in damage to the rib flange.

Not sure what else I can do other than flipping the rivet around so the shop head is on the flange (thinnest part) Vans plans say to but the factory head on the flange to prevent damage. Is doing the opposit structurally unsound? I feel I'm doing much more damage by not getting square on the head.

Go Ahead and Flip it Around

From a structural standpoint, it makes no difference what side the shop head is on.
Terry

An offset rivet set will tend to turn in the gun as you rivet, changing the angle of the set on the rivet. As well as tape on the cup of the set (I use thick hockey tape) put some duct tape across the set and the gun at the gun end of the set. This will prevent the rivet set from rotating in the gun.
Bill Brooks
Ottawa, Canada
RV-6A finishing kit