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Riveting nutplates upper baggage door seal channel.

RandyAB

Well Known Member
Page 33-6 Step 1

Any suggestions on bucking the 426 3-3.5 rivets under the flange overlying the nutplates?
 
Tough to tell from the pictures, and I havent gotten to this step yet. Looks like one rivet in each nutplate you can probably get to by back riveting. Not sure about the other...
 
I don't recall and I didn't mention it in my log, but I 100% sure I did one of two things for those 2 nutplate rivets that are under the flange. I ether used a bucking bar that has a "foot" that could slip under the flange or more likely I just used a blind rivet.
 
Randy, I just reordered this part because I bent up the angle trying to dimple and rivet the nutplates like I do everywhere else. I was thinking I could bend the piece back to original angular dimensions to maintain fit at the baggage door opening = WRONG!

The fix on my end was to countersink the door seal piece and use NAS pop rivets to secure the plate nut on the end under the door seal metal lip. You could do this on both ends of the nut plate if you wanted.
 
My solution..

..was to use my rivet pull dimpler (the one that uses a nail, two small dies and your rivet puller) to make the dimples, then installed a flush pulled rivet in the side that's under the flange.
 
Thanks boys. I machine countersunk for the rivets as per 33-5 step 6 so no dimpling required. I'm going to use a pulled rivet as suggested. I was surprised that the plans called for bucking which I suppose could be done with the right bucking bar.
 
This is a place where you can find or modify a bucking bar to fit. I would not buck those rivets freehand but instead would clamp the bucking bar in a vice, put the work in place over the bar, and drive it normally.

However, think about the context in service. These are used to hold nutplates in place, and mainly against rotation. Screws will be inserted through a lock striker plate, at which point the rivets are both invisible and backed up by the clamping action of the screw/nutplate combination. Also, the channel is fairly thick stock, so it will function just fine if you 1) countersink the channel instead of dimpling both channel and nutplates, and 2) use 3/16" pulled flush rivets there.
 
Thanks boys. I machine countersunk for the rivets as per 33-5 step 6 so no dimpling required. I'm going to use a pulled rivet as suggested. I was surprised that the plans called for bucking which I suppose could be done with the right bucking bar.

You're right. I countersunk those holes, but I did use a pulled rivet in lieu of a bucked one.
 
This is a place where you can find or modify a bucking bar to fit. I would not buck those rivets freehand but instead would clamp the bucking bar in a vice, put the work in place over the bar, and drive it normally.

However, think about the context in service. These are used to hold nutplates in place, and mainly against rotation. Screws will be inserted through a lock striker plate, at which point the rivets are both invisible and backed up by the clamping action of the screw/nutplate combination. Also, the channel is fairly thick stock, so it will function just fine if you 1) countersink the channel instead of dimpling both channel and nutplates, and 2) use 3/16" pulled flush rivets there.

Lol. Ya I agree 100%. For some stupid and unjustifiable reason I always feel a little defeated when I have to deviate from the plans unintentionally.
 
Bucking block/Dimple die holder

I use one of these when I run into a tight spot or a dimple or rivet that needs to be added after the assembly is otherwise completed

https://www.aircraftspruce.com/pages/to/buckingbars/buckingblocks.php


You simply put the male/female dies in place on which ever side works best. A couple of taps with the gun forms a nice dimple, which ever side is on the gun.

It only took a small flexing/distortion of the part to dimple and rivet the part in question. For the riveting portion, I cut the head off an extra set creating a flat face. Using that modified set, and my fingers to hold it in position, I back riveted the nut plates in place. (There was not enough room to get the back rivet set in tight with the plastic shield, thus the modified set with no shield)


A couple of words of caution on dimpling this way; 1. practice on a scrap piece first. It is really easy to make too many hits and leave a smiley. 2. make sure the gun and bucking/die are lined up or you will break the tip off the male die. (ask me how I know). 3. The modified set will bounce so light guiding with fingers or otherwise is needed. DO NOT get your fingers under the set!
I also drilled a 0.187" hole close to the end of a piece of 1" x 1/2"x 12" steel bar (the special bar I made to rivet the elevator skin) to hold dies in awkward places for the same purpose.
 
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