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Goofed Nose Rib - Next steps?

N14KR

Active Member
Section 8 (Horizontal Stabilizer) Page 08-11, Step 3.

Hi All,
I reached out to the mothership a few days ago, and while awaiting a response, I'm very interested in what you all think.

I?ve riveted the middle four HS-905 nose-ribs to the right and left skin.
On the last of the four ribs, the last rivet, I didn?t like the flushness of the manufactured head so I drilled out the rivet.
The head snapped clean off and when I used the punch on the rivet body, it bent out the flange on the nose rib a bit.

I tried using gorilla tape to hold the flange to the skin when re-riveting, but not with much luck; it sticks out. When I re-rivited, it bulged between the two parts.

What should I do about that last rivet? The only thought I had is to drill out the entire rib and replace with a new rib, but I?m quite concerned about ruining the entire skin by having to perform so many drill outs. And then making a small problem a really big, painful, expensive problem.

Picture below:

IMG_0170-small.jpg


Thanks in advance.
 
Drill out the bad river again. Mix up some proseal, inject it between the two parts. Insert cleco to pull the parts together and let it cure. Then in a few days rivet it together.
 
Cut off the little flange, looks to be an inch and a bit long. Take a piece of aluminum angle, the same gauge, and use as a replacement. Drill hole in skin first to the flange and clecoe in place, now drill one or preferably two holes in the other flange to the rib. Remove, clean, dimple small flange hole. Rivet flange to skin, then rivet angle of flange to rib.
This took longer to type then the job will take!

There are of course many variations of this idea.
 
Cut off the little flange, looks to be an inch and a bit long. Take a piece of aluminum angle, the same gauge, and use as a replacement. Drill hole in skin first to the flange and clecoe in place, now drill one or preferably two holes in the other flange to the rib. Remove, clean, dimple small flange hole. Rivet flange to skin, then rivet angle of flange to rib.
This took longer to type then the job will take!

There are of course many variations of this idea.
 
You should be able to squeeze that rivet. For these try taking a piece of small flexible tubing just bigger than the diameter of the rivet and slightly longer. When you squeeze the shop head the tubing will make sure the two pieces of material are held together as the rivet is set.
 
Love these ideas! I don't have any proseal (yet), can I use something else I can find locally just to pull the two pieces together like a silicone or glue for such a small amount before re-riveting? (I remember reading somewhere to only use a certain type of silicone that doesn't react to aluminum).

Maybe use that 3M VHB tape used on the rudder trailing edge?...

The part that is deceiving is this rib is in the middle lower section of the skin...so not reachable by squeezer at all.
 
That's an excellent example of a place not to use a punch to get the shop head out, since it will just push and bend the flange out, as you experienced. Using a punch is more appropriate when access to the shop head prevents the method illustrated below from being used. It should be very carefully applied with something supporting the piece on the back side, like a bucking bar with hole drilled in to accommodate the shop head. That would mitigate the piece from bending out and helps transfer the full force of the punch to the rivet head rather than the material around it.

Page 05-04, Figure 3 illustrates a great method for shop head removal...

F3XQMPJDl5yZHPPpCu0ZfBc8u5SxZ7X6vIk3r79jHukCuh-AxOU29J90gnfcJBhlRmr03PRz_8i3lViRoATvAUAvQD6qjWrz79FAG_Kl3U_0MqIXLzT5JqwKtqvN56yOZl0BIFA0I1o=w640


So, with nine rivets holding that rib in right now, you can consider drilling them out (using flush cutters on shop heads), and replace the rib or bend the flange back (after inspecting that there are not cracks from bending), according to your preference.
 
Last edited:
That's an excellent example of a place not to use a punch to get the shop head out, since it will just push and bend the flange out, as you experienced. Using a punch is more appropriate when access to the shop head prevents the method illustrated below from being used. It should be very carefully applied with something supporting the piece on the back side, like a bucking bar with hole drilled in to accommodate the shop head. That would mitigate the piece from bending out and helps transfer the full force of the punch to the rivet head rather than the material around it.

Page 05-04, Figure 3 illustrates a great method for shop head removal...

F3XQMPJDl5yZHPPpCu0ZfBc8u5SxZ7X6vIk3r79jHukCuh-AxOU29J90gnfcJBhlRmr03PRz_8i3lViRoATvAUAvQD6qjWrz79FAG_Kl3U_0MqIXLzT5JqwKtqvN56yOZl0BIFA0I1o=w640


So, with nine rivets holding that rib in right now, you can consider drilling them out (using flush cutters on shop heads), and replace the rib or bend the flange back (after inspecting that there are not cracks from bending), according to your preference.

Another technique is to stabilize the part with the shop head against the other structure using a bucking bar held just next to the shop head and pop the drilled remnant of the manufactured head with a spring-loaded center punch. I second the use of a piece of tubing (I use aquarium style clear tubing cut to a short length) over the rivet to push the pieces together. May not work well in this instance however - the other methods mentioned may work better.
 
Before doing any of that stuff, reach in with something like a wooden stick and bend the web flat. That by itself might get the flange a lot closer to the skin.

You might need to put a slot in a second stick to simultaneously pull another part of the end of the web from the other side. Maybe not.

A short piece of rubber tube (rubber fuel line works well) on the end of the rivet helps keep the flange pressed against the skin while riveting.

Dave
 
Cut off the little flange, looks to be an inch and a bit long. Take a piece of aluminum angle, the same gauge, and use as a replacement. Drill hole in skin first to the flange and clecoe in place, now drill one or preferably two holes in the other flange to the rib. Remove, clean, dimple small flange hole. Rivet flange to skin, then rivet angle of flange to rib.
This took longer to type then the job will take!

There are of course many variations of this idea.

Do this, but make the tab longer on the rib side, almost to the other skin.

It looks like you may have creased the nose portion of the rib slightly when the flange bit got bent.

Straighten it out and make the added tab reinforce that area. As stated above, 2 rivets should do it, and going one thickness larger in the new tab would help.
 
It's generally a bad idea to try and close the gap by just squeezing the parts together. It introduces stresses in the flange and can cause fatigue cracking down the road. Putting sealant in does nothing to fix this issue.

I like David's idea to try bending the flange back first. You won't get it back to its original position, but you might get it closer. Then you get a piece of aluminum of an appropriate thickness to use as a shim. Try to get no more than 0.005 in. of gap before you shoot the rivet. Adjust the length of the rivet as necessary to account for the additional stack up thickness.

If the shim is bare aluminum you should treat it with Alodine. If it's clad you can leave it alone. Alternatively, sealant around both sides of the shim will prevent moisture ingress and subsequent corrosion. Either way works.
 
It's generally a bad idea to try and close the gap by just squeezing the parts together. It introduces stresses in the flange and can cause fatigue cracking down the road. Putting sealant in does nothing to fix this issue.

I like David's idea to try bending the flange back first. You won't get it back to its original position, but you might get it closer. Then you get a piece of aluminum of an appropriate thickness to use as a shim. Try to get no more than 0.005 in. of gap before you shoot the rivet. Adjust the length of the rivet as necessary to account for the additional stack up thickness.

If the shim is bare aluminum you should treat it with Alodine. If it's clad you can leave it alone. Alternatively, sealant around both sides of the shim will prevent moisture ingress and subsequent corrosion. Either way works.

The shim would be just compensating for the crease at the front of the rib.

Straighten that portion of the rib first by making it flat. :)
 
The proseal idea is good. If you don't have any some JB weld would work - put some grease on the cleco. I would first try to see if I could put a stick in there to press the flange against the skin for riveting but be careful not to create a bulge.

I always drill out rivets with a #41 drill to avoid elongation. It makes things easier and you can still snap off the head and punch out the shank.

If you have 1 rivet out of all of them on a rib that is a bit less than perfect there won't be a safety issue. It really comes down to how OCD you are.
 
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