Need some guidence in regards to riveting 3 parts together

I'm working on the airfoil practice kit and I'm having an issue riveting the spar/rib/reinforcement plate assembly together. Each time I try I end up with a small gap between the rib and the spar. I tried getting a clamp in there but I don't have one small enough to engage and still get the bucking bar in place. What is the trick to this? Thanks.

Often times when forming a shop head against thin material the localized strain induced against the thin material causes it to pucker sightly.
The material is usually still in contact around the perimeter of the hole but puckers out slightly further out.
This is totally acceptable from a structural strength standpoint, but just doesn't look as nice.
This is why best practice is to form the shop head on the thickest material but that is not an option when thinner material is on both side.

Bottom line is that as long as the parts are in contact around the perimeter of the rivet it is a good riveted connection

Rc fuel tubing

I use a piece of rc fuel tubing to push the parts together as the shop head starts to form. This keeps the parts from seperating on inital forming. But I tend to pull the tubing off for the last hits otherwise the shop head tends to come out crooked. Yesterday, I had to use this trick on the bottom skin rivets for the skin to rear spar to rib flange, where the spar is sandwiched between the skin and the rib flange

Windshield washer hose

PilotjohnS said:

I use a piece of rc fuel tubing to push the parts together as the shop head startsto form. These keps the parts from seperating on inital forming. But i tend to pull the tubing off for the last hits otherwise the shop head tends to come out crooked

Click to expand...

Beat me. Windshield washer hose also works if you can't find the clear stuff.

With practice you can learn to swell the rivet and use the squeezer or bucking bar next to the river and lightly squeeze or tap the skin then finish the set. It is really easy to ding a flange until you get the hang of it but it is quick and effective. Try it on your practice piece.

I use a bit of neoprene or rubber fuel line with the -4 rivets. Haven't needed it for the -3 rivets.

Dave
RV-3B, skinning the fuselage