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How could I dimple this hole in an installed rib?

gotyoke

Well Known Member
I miraculously neglected to dimple just this one hole in a bellcrank rib, and I only noticed it now after completely riveting the rib to the bottom skin.

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Since the bottom skin hole is dimpled, there is now a gap. Can't get a squeezer in there, and I can't square up the rod of a C-frame. I considered attaching the male dimple die to a rivet gun and somehow securing the female die on the inside, then had nightmares about figure-8s.

So, resourceful VAFers, how would you go about dimpling this hole in place without drilling out all those rivets? Doesn't need to be pretty, just need a reasonable nesting surface with the bottom skin.

Update: Close quarters dimple die did the trick!
 
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I drilled a hole in a piece of brass I had laying around to accept 1/2 a dimple die and a hole in the end of a brass tipped rivet set to take the other 1/2. turn the pressure down and it's easy to dimple.

You an also drill a hole in a bucking bar to hold 1/2 a die set, then put the other 1/2 in a small socket on the end of a nut-driver and smack it with a hammer.

The previously mentioned pop rivet dies will work as well, although it seems like they don't always pull hard enough to set a crisp dimple, especially when pulling through multiple layers.

Lots of ways to skin this cat
 
Bucking bars

Make a set of these
Put the female die in the bar. Put the male die in a rivet set drilled for 3/16" dies. You can buy one on Aircraft Spruce. Dial down the pressure to about 10 psi. Couple taps feathering the trigger.
 
Pop Dimple

Did the same thing a few months back. Used the Pop-Dimpler 2-3 times, then a light kiss with a CS cutter to clean it up. Worked fine.
 
Make a set of these
Put the female die in the bar. Put the male die in a rivet set drilled for 3/16" dies. You can buy one on Aircraft Spruce. Dial down the pressure to about 10 psi. Couple taps feathering the trigger.

^^
I personally find the results from the pop rivet dies underwhelming. Just can’t impart enough force for a crisp dimple in one skin let alone a skin and a rib or two skins.
If I can get to both sides I’ll always go with Larry’s suggestion even if I have to wait for a helper.
 
I have a back rivet bucking bar that one side of it accepts a die. If you have such bucking bar, you can put the female side on the bottom skin and the male side attached to a long die holder similar to the one that comes with a C-frame and do it from the rib side. This will eliminate the chance of a mishap.

But your simplest and safest way is to use a pop rivet die set.
 
Do the bucking bar with female dimple die as others have mentioned or just countersink the hole.
 
Pop rivet dies will work very well if you use a #6 finish nail rather than the copper or other pullers that are sent with the kit.

Note: A #6 finish nail will barely fit through the dies. The resin that's on the nail may keep it from going through the die. A couple of swipes with Scothbrite will allow the #6 nail to pass though the die.

Fred
 
The pop rivet die might not work well for two sheets already together.
I might have obsessed over this 15 years ago, but it seems to me installing a bolt and fiber locknut would adequately secure this section - and allow you to move on to the next challenge.
 
Update: the close quarters dimple die did the trick.

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With a #6 nail, it was strong enough. Perhaps too stong: I caused a slight deformation of the rib and the skin around that hole. I have decided to accept the blemish...it's not the only one.
 
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