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Tear around hole after dimpling

Golf Echo

Golf Echo

Active Member
Accurately feathering the trigger on a pneumatic squeezer is a very useful skill in producing nice dimples on the rib flanges. Unfortunately, it's a skill I apparently still need to work on... :p

I closed the dies a little too quickly, with a little too much misalignment. About 1 diameter of misalignment. This, of course, made a rather funny looking hole(s)/dimple. Two flat sets in the squeezer flattened this out nicely. But, as you might expect, when I re-dimpled (this time, without the misalignment and twitchy trigger finger) the material around the dimple tore due to the damage from the initial misaligned dimple. I had tried to file/scotchbrite before dimpling the second time to remove any stress concentrations, but I think the initial goof-up did me in.

So, I imagine I need a new rib (VS-706 -- $7.90), but I thought I'd throw it before the court for any other ideas before I pull the trigger on ordering a new one. Thoughts?

The evidence:
IMG_0181.JPG
 
Take a 1/2 inch square of 0.025 scrap, drill and dimple in the center, and use it as a backup plate if you don't want to get a new rib.
 
Graham,
Don't feel bad about not being able to work the trigger on the squeezer perfect every time. I have tried to imagine a crappier design than they use, but can't think of how I could make it worse. I understand it needs to have a double safety, but it could sure be designed better than the current design.

As for the small tear in the rib, I agree with Terry. At that location you probably don't need a rivet at all. Smear a little tank sealant or epoxy on it and rivet it as it is. That is what I would do but it is your plane - your choice!

Have fun with the build and remember almost anything can be fixed!
 
rockwoodrv9 said:
Graham,
Don't feel bad about not being able to work the trigger on the squeezer perfect every time. I have tried to imagine a crappier design than they use, but can't think of how I could make it worse. I understand it needs to have a double safety, but it could sure be designed better than the current design.
.....!
Click to expand...

I'm sure 'elf and saftee would not approve, but I run my squeezer without the return spring.

This way you can move the dimple dies into position with the t**t in the hole before you apply pressure.

Usual caution - keep fingers well clear!!
 
Safety?

The safety feature on the pneumatic squeezer lever seems like more of a detriment than an asset. I disabled mine by inserting a plastic sleeve on the shaft of the lever. It keeps the lever raised in the "ready to smash something" position. As already stated, keep your fingers clear.

So far, so good :D
 
I have two, one at work and one at home. Neither of mine have a safety? Push the lever and it's GAME ON! :)

But yes, it takes a little practice to 'feather' the trigger (lever).
 
Of course I would never admit to altering a tool such as a skilsaw, miter saw, or table saw, by removing the guards or shim them up so I didn't cut my fingers off, but I still have all my fingers after 30 years of construction. The same with the squeezer - but I would never admit that I had done the same thing as others have to make it safer than how it came. It is crazy when what is done to try to protect us makes a tool unsafe and unproductive. I would be willing to bet the FAA had something to do with the trigger design.
 
DaAV8R said:
The safety feature on the pneumatic squeezer lever seems like more of a detriment than an asset. I disabled mine by inserting a plastic sleeve on the shaft of the lever. It keeps the lever raised in the "ready to smash something" position. As already stated, keep your fingers clear.

So far, so good :D
Click to expand...

I'm too trigger happy and have way too little rhythm to disable the safety. After a making a couple of misplaced 3/32 "lightening holes" I make myself consiously let go of the trigger after every dimple to keep from holding it in the "armed" position. After each dimple, I put the male die in the next hole before touching the trigger again. After a few thousand dimples you develop a smooth motion of pushing the trigger out then over.

BTW, I don't know whether that crack is structurally significant, but if it were mine, I'd replace it. Seems kind of early in the project to start making compromises. I have a collection of similar parts in my scrap pile. They make good shim stock.;)
 
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DaAV8R said:
The safety feature on the pneumatic squeezer lever seems like more of a detriment than an asset. I disabled mine by inserting a plastic sleeve on the shaft of the lever. It keeps the lever raised in the "ready to smash something" position.
Click to expand...

What the heck? I did not know there was a safety feature to the trigger! I bought mine used from someone here and it came with a "plastic sleeve on the shaft". I thought it was a field repair and just left it. I like it, though, and would have added it eventually.

DSC00744.JPG


One little trick to smooth squeezing I've found is not to put pressure on the lower (moving) ram before squeezing because it makes it jump or shut too fast. With no or very little pressure, I can feather it closed but every time I put pressure on it, it slams shut.
 
I did the same FUBAR in the exact same spot :eek:... I replaced the rib. If I had it to do over again (after having a bit more know how)... I'd just upsize the rivet and move on. Fast forward a year and now I'm agonizing over a simular situation with a fuel tank skin. :eek:. It happens & will continue as Miles states. Usually there are acceptable fixes, sometimes you'll scrap the part. Welcome to the club. :cool:
 
Word from a "grizzled veteran" ...

In the early stages of the build, ALL of us obsessed over small hiccups like the torn dimple. But as you progress thru the build, three things happen:
a) you realize there are ~16,000 rivets in the aircraft, and one bad one will not ruin its appearance or flyability.
b) there are nearly 8,000 flying RV's out there, and nary a one is 100% perfect. There's a wart somewhere in each of 'em.
c) as you near completion, the desire to FLY that son-of-a-gun far exceeds your tendency or willingness to obsess over small mistakes

"But that's just my opinion. I could be wrong." :D
 
Thanks for the replies and encouragement, everyone. Still not 100% sure what I'm going to do for the fix. The part is super-cheap, but the shipping and wait time are definitely downsides of replacing the part.

az_gila said:
Take a 1/2 inch square of 0.025 scrap, drill and dimple in the center, and use it as a backup plate if you don't want to get a new rib.
Click to expand...

Gil, would this be considered a generally standard/acceptable fix? Or, to put it another way, would something like this be likely to capture and focus an inspector's [negative] attention?
 
Golf Echo said:
Thanks for the replies and encouragement, everyone. Still not 100% sure what I'm going to do for the fix. The part is super-cheap, but the shipping and wait time are definitely downsides of replacing the part.

Gil, would this be considered a generally standard/acceptable fix? Or, to put it another way, would something like this be likely to capture and focus an inspector's [negative] attention?
Click to expand...

I would definitely just repair the hole as Gil suggests, and move on. I'd probably use a dab of epoxy or even hot melt glue to hold the patch in place until it was time to rivet it.

Little repairs like this are just the way things are when you are building your own airplane. Keep things under way and under control. Save the rib replacements for when you really mess up.
 
"Technically" a repair of a rivet hole requires that you span the hole with a patch and put a supporting rivet to each side, or replace that area of the flange, or back the flange with a tab and supporting rivets to the web. That is way overkill and you risk doing more harm than good.
Nobody is going to know that little patch is there but you.
Follow Gil and Bob's advice.
 
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Golf Echo said:
Or, to put it another way, would something like this be likely to capture and focus an inspector's [negative] attention?
Click to expand...

Completely acceptable in a location like that. And no inspector is ever going to see it. Which doesn't mean you can willy-nilly screw up rivets everywhere in the plane, but a little common sense and experience will help you figure out what is critical. Sharing here on VAF is one way, setting up a relationship with a good TC is another (less public) way.

Paul
 
Ironflight said:
Completely acceptable in a location like that. And no inspector is ever going to see it. Which doesn't mean you can willy-nilly screw up rivets everywhere in the plane, but a little common sense and experience will help you figure out what is critical. Sharing here on VAF is one way, setting up a relationship with a good TC is another (less public) way.

Paul
Click to expand...

As always Paul is spot on. One thing I will add to this thread, and try to add to others regarding airframe repairs, (my pet peeve?) is to get a copy or download AC43-13-1b and a second hand airframe mechanics manual from a certified aircraft of similar aluminum construction (spars, ribs, etc...)
These manuals have documented repair procedures for all types of scenerios. Somebody had to do the engineering of them so you can use those examples as a guide to what would be acceptable.
Many think RV's have highly engineered airframes built to today's modern standards. In reality, they are built more like the machines of 70 years ago.
 
JonJay said:
"Technically" a repair of a rivet hole requires that you span the hole with a patch and put a supporting rivet to each side, or replace that area of the flange, or back the flange with a tab and supporting rivets to the web. That is way overkill and you risk doing more harm than good.
Nobody is going to know that little patch is there but you.
Follow Gil and Bob's advice.
Click to expand...

Ironflight said:
Completely acceptable in a location like that. And no inspector is ever going to see it. Which doesn't mean you can willy-nilly screw up rivets everywhere in the plane, but a little common sense and experience will help you figure out what is critical. Sharing here on VAF is one way, setting up a relationship with a good TC is another (less public) way.

Paul
Click to expand...

Guys,

Thanks again for the helpful input. Unfortunately, I'm at least an 8 hour drive from the nearest TC.

Also, here in Canada, we must have a "pre-cover inspection" done for all parts which will form an enclosed structure -- fuselage, wings, ailerons, flaps, etc. This inspection is conducted by a federal inspector, and as I understand it, the inspector will thoroughly check shop heads with an inspection mirror.
Something else I just realized... given that this is the tip rib for the VS, the flange faces outboard and the location isn't exactly inconspicuous.

Thanks for the reference to AC43-13-1b. I imagine most methods would translate to Canadian requirements as well.
 
Golf Echo said:
Guys,

Thanks again for the helpful input. Unfortunately, I'm at least an 8 hour drive from the nearest TC.

Also, here in Canada, we must have a "pre-cover inspection" done for all parts which will form an enclosed structure -- fuselage, wings, ailerons, flaps, etc. This inspection is conducted by a federal inspector, and as I understand it, the inspector will thoroughly check shop heads with an inspection mirror.
Something else I just realized... given that this is the tip rib for the VS, the flange faces outboard and the location isn't exactly inconspicuous.

Thanks for the reference to AC43-13-1b. I imagine most methods would translate to Canadian requirements as well.
Click to expand...

Graham, is it possible for you to know who will do the inspection? I knew my DAR and anytime I had a questionable issue I simply asked him what would be acceptable to him. If not, probably easier to get a new rib than to research, document, and effect a repair should he question it.
I would find it troubling that this small issue would be something that anybody would fail but I don't have any experience with Canadian routines or attitudes.
 
JonJay said:
Graham, is it possible for you to know who will do the inspection? I knew my DAR and anytime I had a questionable issue I simply asked him what would be acceptable to him. If not, probably easier to get a new rib than to research, document, and effect a repair should he question it.
I would find it troubling that this small issue would be something that anybody would fail but I don't have any experience with Canadian routines or attitudes.
Click to expand...

No, unfortunately the inspector isn't assigned until the paperwork is filed requesting the first/pre-cover inspection. Contacts aren't provided beforehand, as apparently the inspectors aren't allowed to coach, help, answer questions, etc.

Sounding like I should order a new rib to avoid an issue down the road...
 
Golf Echo said:
No, unfortunately the inspector isn't assigned until the paperwork is filed requesting the first/pre-cover inspection. Contacts aren't provided beforehand, as apparently the inspectors aren't allowed to coach, help, answer questions, etc.

Sounding like I should order a new rib to avoid an issue down the road...
Click to expand...

That sucks. I would drive a rivet in it and if it really bothered you, fix it later after your inspection as suggested earlier. ( that's coming from a guy who supposedly has a pet peave about airframe repairs )
Or, you could repair as Gil noted and if the inspector had an issue with it, you could still remove the rivet and fabricate a flange backer secured to the web. That is an acceptable repair, or at least should be....

I think you have enough to think about Graham. Do what you feel comfortable doing but know that there are many more little oops coming down the line..... Isn't building an airplane fun?
 
JonJay said:
That sucks. I would drive a rivet in it and if it really bothered you, fix it later after your inspection as suggested earlier. ( that's coming from a guy who supposedly has a pet peave about airframe repairs )
Or, you could repair as Gil noted and if the inspector had an issue with it, you could still remove the rivet and fabricate a flange backer secured to the web. That is an acceptable repair, or at least should be....

I think you have enough to think about Graham. Do what you feel comfortable doing but know that there are many more little oops coming down the line..... Isn't building an airplane fun?
Click to expand...

Yeah, I'll do some thinking on it tonight. I'll see if I can find what's required for attaching the backer to the web, and maybe I'll just go that route from the beginning. I'm thinking it should be pretty easy to fabricate.

I feel like I've already got a significant number of oopses under my belt, but I'm sure I can manage some more as the build progresses... I'm still trying to settle on a solution for my HS rear spar "oops". ;)
 
OOps Rivet

Golf Echo said:
Accurately feathering the trigger on a pneumatic squeezer is a very useful skill in producing nice dimples on the rib flanges. Unfortunately, it's a skill I apparently still need to work on... :p

I closed the dies a little too quickly, with a little too much misalignment. About 1 diameter of misalignment. This, of course, made a rather funny looking hole(s)/dimple. Two flat sets in the squeezer flattened this out nicely. But, as you might expect, when I re-dimpled (this time, without the misalignment and twitchy trigger finger) the material around the dimple tore due to the damage from the initial misaligned dimple. I had tried to file/scotchbrite before dimpling the second time to remove any stress concentrations, but I think the initial goof-up did me in.

So, I imagine I need a new rib (VS-706 -- $7.90), but I thought I'd throw it before the court for any other ideas before I pull the trigger on ordering a new one. Thoughts?

The evidence:
IMG_0181.JPG
Click to expand...

I can send you a few NAS1097 rivets, the shank would be 1/8th and the head is real close to the AN426AD3,s
 
GAHco said:
I can send you a few NAS1097 rivets, the shank would be 1/8th and the head is real close to the AN426AD3,s
Click to expand...

Tom,
I appreciate that very much. Unfortunately, the crack extends well beyond what would be covered by drilling out to #30, so an oops rivet won't really solve the problem.
 
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