Newbie riveting question

jlott · #1 08-21-2011, 07:38 PM

I'm currently working on the Practice Kit and should be ordering the empennage in the next week or so. I ran into a small problem today riveting the ends of the practice kit project (the reinforcement/spar/rib combination).

Basically, when the shop head of the rivet is being formed the rib flange wants to lift up off the spar leaving a gap once the rivet is set. I played around with a number of different ideas to prevent this but I'm not sure if its possible.

Is there some way to prevent this gap from forming?

Jerry Fischer · #2 08-21-2011, 07:55 PM

Clamping the two pieces together either with a spring clamp or a small u clamp available from most avion tool supply stores.
You just need to keep the metal sandwiched together when riviting, and normally on more lengthly pieces, clecoes in the surrounding holes will clamp sufficiently. I hope this helps. BTW sometimes your local Harbor Freight Aviation Dept

has the clamps you need.
Keep on riveting!

Greg Arehart · #3 08-21-2011, 07:56 PM

That shouldn't happen. One way to mitigate the problem might be to bend the rib flange ever so slightly so that when you cleco the middle hole it pulls the ends of the flange up against the spar. Rivet the end holes first (leave clecos in the holes you are not riveting), then do the middle hole.

Usually, squeezing or driving rivets will pull the two pieces of sheet metal together unless the gap is considerable.

Hope this helps.

cheers,
greg

sstellarv10 · #4 08-21-2011, 08:01 PM

You will find it will happen when the shop head is put on the thinner material which is where it needs to be in this case. When you get into your project you can put the manufactured head on the thinner material when possible. Squeezing the rivet just a little too hard will cause the thinner material to lift up, it will take a little practice but take some thin scrap and you can see how much squeezing it will take to distort around the rivet.

jlott · #5 08-21-2011, 08:01 PM

Quote:

Originally Posted by Jerry Fischer

Clamping the two pieces together either with a spring clamp or a small u clamp available from most avion tool supply stores.

Yeah I tried the spring clamps that I have but the space is so small... cant really get them onto the very corner of the flange. I will try to find a smaller clamp.

Quote:

Originally Posted by Greg Arehart

... the middle hole it pulls the ends of the flange up against the spar. Rivet the end holes first (leave clecos in the holes you are not riveting), then do the middle hole.

Sadly, there is no middle hole. Just two rivets hold that flang against the spar in the practice project.

Thanks for your responses guys!

RV6AussieNick · #6 08-21-2011, 08:25 PM

Looks to me that you might be over driving the rivets, a properly driven tail should be 1.5 the rivet dia, another good rule of thumb that someone mentioned above about having the head on the thin side and forming the tail on the thick, the puckering in your photo is a good example of what happens with tails formed on thin material.

Good luck with your build,

Cheers Nick

Greg Arehart · #7 08-21-2011, 08:41 PM

Quote:

Originally Posted by jlott

Sadly, there is no middle hole. Just two rivets hold that flang against the spar in the practice project.

Use that cleco jaw clamp in the background of your photo to hold it together in the middle.

greg

jlott · #8 08-21-2011, 08:43 PM

Quote:

Originally Posted by RV6AussieNick

Looks to me that you might be over driving the rivets, a properly driven tail should be 1.5 the rivet dia

I'm constantly worried about that actually. First rivet I ever drove in my life was on the toolbox kit

The rivets in the photo measure OK using a rivet gauge for both height and diameter of the shop head. You guys all know a lot more than me though.

Thanks!

Av8torTom · #9 08-21-2011, 09:04 PM

You should be able to bend the flange slightly as Greg stated so that it sits firmly against the spar. Give it a try - won't take much.

WenEng · #10 08-22-2011, 02:05 PM

Sometimes you will find that if your triple work is not clamped tightly, when you squeeze the rivet, the rivet shaft expands slightly between layers forcing a bad fit. It is probably the camera lens, but it looks like you are not squeezing perpendicular to the hole, or perhaps the hole was match drilled at a slight angle. Probably just the camera lens, though.