KMinor

KMinor

Active Member
I don't like it, but I'm afraid to drill it out. It's the third center rib from the inboard side of left wing, up against the front spar flange bar. I read back over Section 5, but don't feel like I have enough experience to make a decision. So I'd like to see what the consensus is. Thanks ahead of time.
14azcr4.jpg

http://i40.tinypic.com/14azcr4.jpg
 
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Drill it

Edit I have been out voted! :)
Make a practice piece!
I would go after the back side with a #40 and drill little below the surface of the spar to relive the internal stresses that are holding it tight in the hole. The drill bit can be held at any angle, just so long as it stays on the tail, and the face of the bit is approximately centered when it reaches the face of the spar, From then on out it needs to be squared up.The chisel needs to be ground similar to a carpenters chisel, with the corners rounded so they don't catch or gouge with an edge. Easy enough to check by "scraping" a scrap piece of metal. Cut off the tail (chisel), then whack it with 3/32 punch or smaller. If it doesn't break loose with a few light taps, then you are resetting it. Touch it with the drill again. Once it starts to move, make sure its is coming out of the rib as well. It should. The rivet has swollen more in the thin rib than the thick spar (that's why I would go after it from the back side) If not, get some one to back it. Backing it only works if it starts to move in the rib, if not, then you are just bending the rib. Stop, either touch it with the drill again or get under the head with you sharp chisel and see if you ca "roll" it out or at least get it started. If you end up going all the way through with the 40, and you have not removed anything but rivet, start stepping up drill sizes a few numbers at a time until it breaks loose. Good luck, and remember if it's not working, stop and do something different, or nothing at all until the answer comes.
 
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Not pretty, but I've seen a writeup where horrible cases of riveting nevertheless retained 90 or so percent of the design strength.

Being the spar and where this is, I'd hold my nose and continue building after promising myself not to do it again.

Dan
 
drilling rivet

I had to drill one. I got it out without damage but would think twice about doing it again. It was tight and despite popping the factory head, the rivet did not want to let go. I used a small socket on a bucking bar to prevent distortion of the parts. It sure got me to pay extra attention to the rest.
 
The experts say not to, but I use a drill size a couple of sizes smaller then the hole and drill deeply into the rivet to relieve stresses and they usually come out without pounding.

Just me. No science, I am just lazy and don't like hitting a rivet in thin materials. YMMV
 
I vote for leave it also, I have messed up a rivet or ......two and made it worse by trying to drill it out. I found that, the longer the rivet, the higher the chance you will not succeeded.
 
Come look at the riveting in my 47-year old Cessna 150. These types of riveting mistakes are common in it and much worse. Still going strong. Build on.
 
Thanks guys! I left it as is. I probably got better at drilling them out than putting them in on the tail kit, but that long rivet through that pretty spar scares me. Thank you for the reassurance!
 
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