[mdredmond]

I mis-drilled a skin-to-rib hole very slightly about mid-chord on my HS. The hole is slightly oblong by about 1/32" (used an accurate rule to measure).

Do I need to drill this oversize and use an 'oops' rivet - or will the standard size rivet expand enough to mitigate the damage?

This is the only hole I've messed up on. The problem won't cause any appearance issues and my gut feeling is to just ignore it - there's 8 million rivets back there and this is just one. But I'd like a second (and third) opinion...

 

[alpinelakespilot2000]

Assuming edge distance will allow it, and assuming you haven't already riveted anything together, I'd drill it up to a 426-4 and dimple that one hole accordingly. Otherwise I'd use an oops. It will be tough to get the 426-3 to set correctly. You'll mess up many more holes in the future, so don't worry about your first! Good luck.

 

[mdredmond]

..but a standard AD4 rivet will appear bigger, right? I thought the appropriate oops rivet is a AD4 shank but with a shaved-down head that looks like the AD3...

 

[Rene Bubberman]

Yep, that's correct. Just matchdrill with a #30 and use an Oops. And do not worry: you'll become very creative solving these kind of problems

 

[alpinelakespilot2000]

..but a standard AD4 rivet will appear bigger, right? I thought the appropriate oops rivet is a AD4 shank but with a shaved-down head that looks like the AD3...

Yes, Matt, you're right. It will appear bigger. The reason I suggested it is because it would be stronger than the oops rivet. Granted, most of the force on this rivet is probably in sheer, for which the oops will serve quite well, but the tensile strength of a full size AD4 is much greater due to the larger surface area of the manufactured head. This would definitely be my suggestion if your skin hole is oblong. You'd need the larger manufactured head to cover up that mistake. Also, unless someone is really looking hard, they won't notice the larger rivet head, especially if you'll be painting your plane when you're done.

Again though, as Rene suggests, if the only problem is with the hole in your rib, the oops rivet is just fine so long as you don't have too many of them. In my experience, you'll have a number of places on your plane where you'll have to use them because you can't re-dimple. My philsophy has been to save them for that purpose and always go with the strongest option to fix a mistake. Just a preference of mine though. Good luck as you finish the HS. Hope you're having as much fun as I had!

 

[RScott]

How to make your own oops rivets of any size

Got a squeezer?

For slightly oversize holes, here's what to do: Measure the length of the rivet that's called for and adjust your squeezer for that length (or adjust it so you can just fit a rivet in you squeezer, holding it with tweezers or something other than your fingers). Stand your squeezer on end, put a rivet of the next longer length in your squeezer and squeeze. The result will be a shorter, fatter rivet and it doesn't matter if the modified rivet didn't come out to exactly the length called for.

For a slightly egg shaped hole, the rivet won't care if it is egg shaped, it will fill the whole hole.

If the rivet came out too fat, just squeeze another, but don't make it so short.

I have done this about a couple dozen times & they work just fine. I also do this if the fit of the rivet in the hole is just sloppy.

Related note, since you are apparently just starting: Think twice or thrice before drilling out rivets. Too often the replacements end up worse than the rivets you are intending to replace & your egg shaped hole is a good example. These planes have an excess of rivets so an occasional clinched or overdriven rivet between good rivets won't make the plane fall out of the sky.