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Tough set of rivets on tail cone under J stiffeners

MElstien

Well Known Member
Hello, I am riveting the tail cone skins to the bulkeads and came upon a few rivets that I cannot figure out how to set. These are several rivets that join the bulkhead to the skins but fall under a J-stiffener. How do you get to these? Blinf rivet?

In this picture, it is very hard to truly see the rivet is completely under the J-Stiffener. Others were close and I able to use the edge of my back rivet set.


http://elstien.us/RV-10 Build Log and Information/Picture Albums/Tail Cone/DSC05133.JPG

On another note, I clekoed the skins from the inside and back riveted almost 100% of the rivets except the very back of the tail-cone. It came out very nice.

Any help or advice would be appreciated.
 
Bucking bar use

Thank you Eric. I have a few of those bucking bars. Never used them. I am so used to my tungsten bar. I guess I could break them out. I wont be able to back rivet them though.

Let me try that tonight after my meeting. Hopefully I wont forget to lay down a blanket on the bottom skin to prevent dropped bucking bars from making dents.

I cannot believe how light the tail-cone is getting once all assembled and the clecos are removed.

Thank You
 
I backriveted most of it as well. Amazing how well the rivets set. I reaaaallly wish I would have figured the back-rivet method out before I assembled my rudder. That piece would have been done in a heartbeat with a better outcome and no ruined skin. (I ended up replacing one of the skins when I backriveted off the edge of the bar after reading countless warning about not doing exactly that!)
 
I backriveted most of it as well. Amazing how well the rivets set. I reaaaallly wish I would have figured the back-rivet method out before I assembled my rudder. That piece would have been done in a heartbeat with a better outcome and no ruined skin. (I ended up replacing one of the skins when I backriveted off the edge of the bar after reading countless warning about not doing exactly that!)

I did the same thing - I suggest a little, but powerful, magnet to locate and sit at the end of the plate. Like a neodymium disc magnet. I got several from Amazon and used some for aluminum vice jaw covers.
 
Thanks - those rivets are done and I am moving on

Thanks everyone for the feedback. I used the bucking bar suggested, with some electrical tape wrapped around it to protect near-by primed surfaces. It worked well.

I have a whole set of various bucking bars but nothing compares to the tungsten. I forgot I even had them.
 
Let me know how Page 10-21 Step 3 goes for you. I had a heck of a time with the rivets closest to the skin between the Bellcrank ribs and the F-1007 frame. Even with an offset rivet set, I could get a clean set. I finally ended up using pulled rivets. Unfortunately, I buggered the holes up a bit and had to fabricate a doubler, an approach OK'd by Vans.

If there's no clear way to get those rivets done, just use pulled rivets rather than causing yourself frustration...
 
Bellcrank ribs to skin riveting

I still need to rivet the bottom skins in place but most of that should be easy. I will need to phone a friend for the few rivets on the bottom curved piece, then it is on to section 10-21

I was looking at that section a few days ago and was wondering why not attached the bellcrank ribs, 10-21 step 3 before attaching the angle to the top of them (section 10-21 step 2)? Then I would not need an offset set. I could simply back rivet them on place.

Thoughts?
 
The rivets I was referring to were the 6 AN470AD4-4 joining the bellcrank ribs to the F-1007 frame. The ones nearest the skin are a pain.

It looks like you should be able to rivet everything up prior to attaching the F-1037B & C rob angles but that's not the way I did it. If you're thinking about doing it that way, I'd cleco everything up and make sure you have all the access you need to get to those rivets without things becoming too awkward. It would be a real pain to have to drill out all those skin rivets if things went bad.

The upside of your approach would be that you could likely get the rivets closest to the skin with a bit easier.

Personally, I'd just follow the plans but substitute pulled rivets on the two PITA rivets closest to the skin. IIRC, the skin rivets on the bellcrank ribs were a breeze. Just use a swivel mushroom set, some tape over the rivet heads to protect the skin, and your tungsten bucking bar. As long as you have a rivet buddy anyway, those should go quickly.
 
Question on rivet hole size

Any help or advice would be appreciated.

Question: the hole looks like is was dimpled with the wrong size dimple and is oversized. The rivet should be the same diameter as the un-bucked rivet. Are all your rivet holes oversized? There is a tolerance in the mil-spec on hole size.
 
Hello, I have been traveling and unable to respond with proper information. I must say I was worried about the comment about the oversized hole. I am glad when I got home I was able to do some research and take some measurements.

Yes, that hole does look larger than it should be. I do not know why. That rivet, has been set and I cannot go back now and re-measure. But, I can use any parts that have not been assembled yet to check my work and recheck my dies. I use Cleaveland Tool dies, but I do have other sets as well.

I know I dimpled all those bulkheads and J-Stiffeners at one sitting with one set of dies in the pneumatic squeezer. I know when dimpling the J-stiffeners and bulkheads and anything with a flange, I used the small diameter dimple die. The only small diameter die I have is a -3 from Cleaveland. I use the small diameter die to make sure the outer edge of the die does not fall over the bend in the flange and deform the part. (I did that once on my sample airfoils)

So I went and measured the dimples of those parts on the pieces that I have not assembled yet. The upper skin J-Stiffeners, the bellcrank ribs etc. All the dimples conform to the measurements in the below pictures and thread links at 0.103 or 0.104. (Not the larger substructure hole diameters). Nothing larger. Does this meet the mil-spec listed, no, but the mil- spec does not cover dimpled holes, only countersunk holes for 426 rivets. This forum has many threads on this topic. I copied one with pictures into this post. My holes that have not been dimpled, the longeron holes, have a nice tight rivet fit as per MIL-Spec.

I then took all my -3 dimple dies and proceeded to make test runs in all various combinations to see if maybe, one was mis-marked or larger than it should be. They we all OK. To quote Warner Wolf (NY Sports Broacaster), lets go to the video Tape. I went and viewed my dimpling and confirmed that all J-Stiffeners were dimpled using the same pneumatic squeezer and dies at one sitting. (1-24-2016)

http://i601.photobucket.com/albums/tt98/h60av8tor/BC073CD4-B86E-432B-B2C9-0BB99C6EB99B.jpg

Thread http://www.vansairforce.com/community/showthread.php?t=123000&highlight=dimple+diameter

I believe I am OK and that picture is deceptively showing an excess amount of gap. I will review all those rivets later tonight.
 
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