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Rudder skin riveting

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gregsrv14

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I final-drilled all the rudder skin holes and stiffener holes with a #40 drill bit, deburred them, then dimpled them with a 3/32 dye.

Squeezing the first couple of AN426AD3-3 rivets gave me 9/64 diameter shop heads with what appears to be at least 3/64 height.

But they do not cover the rim of the dimpled hole. In fact, they almost look like they could very easily just slip out of the holes.

Looking at the holes more closely, I see that the rivets sit quite loosely within the dimpled holes. Should this be the case? (4-diameter rivets do not fit in the holes.)

Is this all normal? As far as I know, I have done everything exactly according to the plans.

Should I try 3.5-length rivets to get a wider shop head? Open them up to 4-diameter holes? Do I need to start over?
 

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gregsrv14 said:
I final-drilled all the rudder skin holes and stiffener holes with a #40 drill bit, deburred them, then dimpled them with a 3/32 dye.

Squeezing the first couple of AN426AD3-3 rivets gave me 9/64 diameter shop heads with what appears to be at least 3/64 height.

But they do not cover the rim of the dimpled hole. In fact, they almost look like they could very easily just slip out of the holes.

Looking at the holes more closely, I see that the rivets sit quite loosely within the dimpled holes. Should this be the case? (4-diameter rivets do not fit in the holes.)

Is this all normal? As far as I know, I have done everything exactly according to the plans.

Should I try 3.5-length rivets to get a wider shop head? Open them up to 4-diameter holes? Do I need to start over?
Click to expand...
3-3 rivets may get the job done, but I switched to 3-3.5s because it didn't look adequate to me either
 
Hole size looks excessive. Deburring should not enlarge the hole. Make sure you only remove the burr and no more. I would also check the dimple dyes. Quality dimple dies are well worth the money if that turns out to be the problem.
 
ryoung said:
Hole size looks excessive. Deburring should not enlarge the hole. Make sure you only remove the burr and no more. I would also check the dimple dyes. Quality dimple dies are well worth the money if that turns out to be the problem.
Click to expand...
Yes, they look excessive to me too. What should I do?

The dimple dyes are from Cleaveland and I've measured this one to be exactly 3/32".
 
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gregsrv14 said:
The dimple dyes are from Cleaveland and I've measured it to be exactly 3/32".
Click to expand...
Cleveland used to sell a sub structure die and a tank die set. Not sure if they still do. Both would create a larger diameter hole than a regular die set. Any chance you have one of those sets? What’s stamped into the side of your die set?
 
One thing you might try. Take some AD3-3.5 or -4 rivets and pre-squeeze them to help fill the hole better before actually setting the rivets. I would make up some practice pieces to work on before trying this on the rudder skin and only if the practice pieces are satisfactory. I would not upsize to a AD4 rivet, you will likely not like the result.
 
mc607 said:
Cleveland used to sell a sub structure die and a tank die set. Not sure if they still do. Both would create a larger diameter hole than a regular die set. Any chance you have one of those sets? What’s stamped into the side of your die set?
Click to expand...
I do not have one. The die is stamped "3/32". I measured it with calipers and it is indeed 3/32.
 
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Why are you final drilling? I am under the impression that the 14 kit has all holes final sized.
Is there a good fit between your pieces, does the skin lay down well?

What EXACTLY are we looking at? While not familiar with the 14, my 10 rudder had me DIMPLE the TOP skin and COUNTERSINK the FRAME part. That really looks like maybe you dimpled both. Edit, my stiffeners were dimpled, not countersunk
 
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Rivet in your first picture looks fine to me, remember shop heads in dimpled material 'appear' smaller because they fill a V
shaped hole.
Don't over squash those rivets on that thin .020 skin. You will end up with a pucker stretch around each skin hole.
Also remember to apply a small dab of sealant (adhesive) under the end of each of those stiffeners to prevent cracks later.
 
My die is from Cleveland and it says 426-3. Where did you buy your dimple die? Are you back riveting the stiffeners in the pictures above? Van’s is a great kit plane supplier but they are horrible at updating drawings in a timely manner. I just checked a Right hand rudder skin I have left over and the holes that accept the stiffeners (the ones you backrivet) are all punched final size, #40. There is no reason to run a drill bit through those holes. Also, there is usually no reason to debur a factory punched hole. I suspect that when they went to punching those holes final size they didn’t update the plans. Page 07-09 has you bond the trailing edge, and the next page it tells you to peel it back to get access to those rivets. I remember pointing that out to them years ago. Sorry for the rant, but my point is, don’t follow the plans blindly. They are very good but not perfect.
If you are back riveting the stiffeners, you may be able to switch up to a 3.5 length rivet, as mentioned by Mark, and get an in spec shop head. Keep in mind that with an oversized hole, which yours appear to be, the shop head will have a tendency to lean over. I would duplicate exactly what you’ve done on your rudder with a row of holes on a scrap piece and back rivet a bunch of 3.5 length rivets and post the results.
 
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I thought your dimpled part looked to have a larger hole and had to go out to my shop. 3/32 dimple, 3-4 rivet, length not important. I think this looks similar to your photo, makes me think the idea to use longer rivet is right.
 

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RNB said:
Why are you final drilling? I am under the impression that the 14 kit has all holes final sized.
Is there a good fit between your pieces, does the skin lay down well?

What EXACTLY are we looking at? While not familiar with the 14, my 10 rudder had me DIMPLE the TOP skin and COUNTERSINK the FRAME part. That really looks like maybe you dimpled both. Edit, my stiffeners were dimpled, not countersunk
Click to expand...

The 14 has a lot of final drilling. I have seen people suggesting using a 3/32 drill bit instead of a #40 (I believe the #40 is 0.0043 larger than 3/32). The pieces do lie down nicely together and almost feel as if they're locked together.

If I recall correctly, both the stiffeners and the skins dimpled (I will update if not). The photos are the shop head side of the rivets, so we're looking at the stiffener, with the skin hidden below it.
 
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RNB said:
I thought your dimpled part looked to have a larger hole and had to go out to my shop. 3/32 dimple, 3-4 rivet, length not important. I think this looks similar to your photo, makes me think the idea to use longer rivet is right.
Click to expand...
What does the squeezed rivet look like? Does the shop head cover the rim of the dimpled hole?
 
gregsrv14 said:
What does the squeezed rivet look like? Does the shop head cover the rim of the dimpled hole?
Click to expand...

My rudder is completed and I recall things looked better than yours. If I squeeze one now on practice metal it would not duplicate your exact scenario.

www.vansaircraft.com

RV-14 / 14A - Van's Aircraft Total Performance RV Kit Planes

www.vansaircraft.com www.vansaircraft.com
At the above link. under build the RV14 it says everything is final sized.

On my 10, if the rivet fits, I do not drill again!
If the rivet fits, what or why does it need drilled again?
 
This is probably closer to what you might expect after your rudder stiffener rivets are set.

1758484357263.png
 
Here’s a picture of the stiffeners for the wing root fairing. Same size rivet, thicker skin. The big arrow is in the picture because that was the last rivet to set, in my build…🥲
20250806_194751.jpeg
 
RNB said:
My rudder is completed and I recall things looked better than yours. If I squeeze one now on practice metal it would not duplicate your exact scenario.

www.vansaircraft.com

RV-14 / 14A - Van's Aircraft Total Performance RV Kit Planes

www.vansaircraft.com www.vansaircraft.com
At the above link. under build the RV14 it says everything is final sized.

On my 10, if the rivet fits, I do not drill again!
If the rivet fits, what or why does it need drilled again?
Click to expand...
These definitely need drilling. The Clecos would not go into the holes prior to drilling. But that is good advice to check things first in case some places are already final-drilled.
 
Agree on the upscaling of the rivet size. Its a great "when in doubt" change to make. Be wary of "cleating over" when the tail of the rivet gets too long. If your squeezed rivets have nice round shop heads, you are good. And don't be afraid of making some "custom" length rivets in the future. You can take a 3.5 (or whatever) and make it slightly smaller on a sanding wheel.
 
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