How did the holes in the ribs get too big?

carrollcw · #1 03-20-2012, 07:30 PM

So, I am assembling the horizontal stab for a -7. I am to the point where it is time to rivet the skin to the ribs. When I went to Cleco the skin to one of the ribs, I noticed the Cleco would not grab the rib! I checked the rest of the ribs, and 4 of them will not hold the Cleco! The holes are not large enough for the next bit size (so I know I didn't drill them wrong) but they are clearly too big for the Cleco and rivet! Also, I dimpled all the ribs at the same time, so its not like the dimpler was set wrong.

So, what do I do? I could Cleco from the rib to the skin (since the skin will hold a Cleco) and go ahead and rivet. Or, I can drill and dimple up one size rivet, but that will be a major PITA!!!

So, 2 questions:

1) What should I do?
2) How did this happen? Did I get some ribs that were predrilled too big? It makes no sense!!!

Thanks!
Clark

rv7boy · #2 03-20-2012, 07:50 PM

My first thought is it could be your Clecos. There was another thread recently where several builders were complaining about inferior Clecos not holding just as you describe. Try switching your Clecos around or maybe even borrow Clecos from another builder. Hope you find a simple fix.

Av8torTom · #3 03-20-2012, 07:51 PM

Some pictures might help. How do the rivets appear to fit in the holes? Have you tried to set any? I'm wondering if your clecos are defective.

Tom

bret · #4 03-20-2012, 07:56 PM

just a thought, but did you maybe open up the skin a little too much to dimple, and maybe this is just too much spring back pressure of the skin for the cleco to grab hold, I think mine was like this?

carrollcw · #5 03-20-2012, 08:22 PM

I was using a pneumatic squeezer with the same dies and setting for all the ribs. As to the rivets, you can definitely tell there is more wiggle room compared to the standard rivets that I have set. Clecos worked fine before dimpling. I am thinking redrilling to next size is overkill. Leaning towards installing clecos from inside and making it work, but waiting for more responses!

Vlad · #6 03-20-2012, 08:24 PM

Cleco little pieces of aluminum properly drilled #40 to back up enlarged holes. Rivet them and forget them. Use proper technique on the next batch.

gstone · #7 03-20-2012, 08:26 PM

I must have ordered the 40 size clecos in two different sets or something because mine are distinctly different. You can hold them up and see the tiny ones that only have a small curve in the tangs versus the better ones that have a larger curve. I have mine seperated into two bins, the small ones work ok on metal that hasn't been dimpled but don't work at all afterward....

Good Luck!

Stalldog · #8 03-20-2012, 08:27 PM

Are you positive you used the right die set for the dimples? If drilled right and dimpled with the right die set, looks like about all it could point to is clecos IMHO.

bird · #9 03-20-2012, 08:48 PM

It is probably normal after dimpling in the really thin skin. You will find that along in the build when you have thicker skins the problem will go away.

bird

rv7boy · #10 03-20-2012, 08:57 PM

Isn't Friendswood near Houston? I'm sure there are several RV builders near you. Check the RV White pages and contact an experienced builder to come over and offèr an opinion. Even a phone conversation may help you.
P.S. make sure your pneumatic squeezer isn't affecting your die/hole alignment during it's action.