M

Mohammed

Active Member
Patron
Hi
I came across my first bad rivets and I had to drill them out. As many may had done I slightly enlarged two holes in the process. Those rivets are flush head size 4-7 and they are the ones attaching the Vertical Stab aft spar VS-803 to the spar doubler VS-808 to the hinges bracket VS-410PP



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What do you suggest should I do?

1) Use same size rivets assuming the small gap will be filled be the rivets and that the rivets lines along the spar will ensure that the spar and the doubler are in one piece and the remaining four rivets will bear the load on the hinges?

2) Replace the hinge bracket with a new one so the shop head will have enough material to hold on.

3) Enlarge the holes to the next size and use larger rivets though I am not sure if I can meet the minimum edge distance requirement.
 
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One trick is to take a longer rivet of the same size and 'pre-squeeze' it using a hand squeezer to swell the shank. Then drive it normally. This helps prevent it 'clinching' instead of driving straight.

Even if it drives straight, the original rivet length will probably yield a too-small shop head if the hole is oversize and you're dealing with thick materials.

Charlie
 
Edit: Now that I see they are flush rivets, I agree with below post. Relatively cheap to do over if you're not 100% happy with it. I have a whole pile of empennage parts...
 
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Trouble is usually on a flush rivet you will knife edge the part when you step it up to a larger rivet which is unacceptable.

If they are thick enough to accept a -5, which I doubt, then go ahead and step it up (for a -5 CS rivet .050 would be minimum sheet thickness)
(Standard practice is to limit countersink depth to 2/3 the thickness of the sheet).

These are critical components and the workmanship needs to reflect that. If its not right just buy new parts and do it over.

PS: and please resize your pics so they fit on the screen.
 
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Hi. I'm not a regular. I'm here because of Tony Kelly. Anyway I worked for Gulfstream a year building aircraft. Oversize holes goes with the job. We drilled them out to the next larger size and stuck a rivet in it. FAA inspectors oversaw everything we did and anytime you needed to do something out of the norm they would tell you what to do. If they couldn't one of the engineers could. So don't think you ruined a part because of an oversize hole. We fixed rips in holes with oversize holes. I don't know how far you can go oversize but I really don't remember hearing people scrapping parts. There is normally a fix for something. There was a sign hanging from the ceiling in the plant which read "If you're not making mistakes then you're not working." So don't worry when you make one.
 
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