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Another hole enlarged question....PLS HELP!

HighSchoolBuilders

Well Known Member
Hi everyone!

I run into another problem with hole enlargement when drilling out defective rivet. This time it's on the F-804G-1 Vertical Bar at the Center Section, the drill managed to depart on the pre-drilled hole and make its way to make a nice "8" on the other end.

It also damaged the F-804B-1 Center Section Spar web and F-804C bulkhead.

I consider enlarge the hole next size up, but before I do so, I would like to if anyone has a better idea. Another thing is it requires a fairly long rivet (-14), which I need to special order.

Another fix is drilling a new hole between the damaged hole and the AN bolt and leave the damaged hole empty.

The F-804G-1 Vertical Bar has two AN4 bolts and two AN426 rivet holding it in place. Is leaving the damage hole empty an acceptable option?

Many thanks!
Hank
CAPTION:
1st photo shows the enlarged exit hole of the F-804G-1 Vertical Bar, and the enlarge hole on the center section web.

2nd photo shows the damaged hole on the F-804CF Bulkhead, where the shop head is suppose to form.

1.jpg


2.jpg
 
I'll let others chime in on how to fix this.

However, it looks like your technique for drilling out rivets is incorrect. The idea is to not drill all the way through the material. My technique for drilling out 1/8 inch rivets is to use a 3/32 bit and drill into the manufactured head. Take another (older, dull) 3/32 bit, turn it around backward and stick it into the hole you just drilled in the rivet and work back and forth until you pop the manufactured head off the rivet. Now the rest of the rivet should pull out of the other side or you may need to grab the shop head with some needle nose pliers. Sometimes the rivet may get stubborn and you'll need to enlarge the hole in the shop head to 1/8 and work it with a 1/8 inch bit.

This technique does work and it works well but it takes some practice. When I built my wings I realized that I screwed up the flap braces and had to drill out every one of those 1/8" rivets.

2005-04-01.587.jpeg
2005-04-04.609.jpeg
 
Hank, it would be acceptable to open the hole to the next size and install a new rivet. I would not drill a new hole and leave this one empty.

For future rivet removal (and there will be more to drill out, trust me), you might consider buying a rivet removal tool:

528.jpg


$59.00 from Avery tools. This tool will positively center the drill bit on a standard AN470 "universal" rivet head. And the drill depth is adjustable.
 
Drill the hole out before you order a rivet - it looks like you may have to go up two sizes to get a clean hole. Jamie's technique works well but sometimes in thicker material you have to be a bit creative. A driven rivet expands to fill a hole and may resist coming out. Drill into the head until you can pop it off and then carefully drill into the shank about 1/32" or so. Then use a 3/32" punch to begin driving out the rivet. You'll need a friend to help; they should back up the work with a bucking bar on the other side. One with a hole big enough for the shop head to go into is ideal as it will support the work all around the rivet but you can usually get away with using an ordinary bar placed right next to the shop head. With the work supported, drive the rivet back through the hole using the punch and a hammer or rivet gun. When the rivet has moved far enough that the original hole is exposed (that first 1/32" you drilled is almost never perfectly centered), you can now switch to a 1/8" punch and drive the rivet out the rest of the way. Depending on how badly off-center your initial drilling was, you can either just drive a new rivet or put a bit of structural adhesive in there (epoxy, aluminum filler, or the like) and re-drill from the other side before setting a new rivet. Worse case, drill out a size larger, again from the other side where the hole is still in good shape.
 
+1 for a bolt/screw

Yep, I'd go with a bolt. You'd probably need to go up to a 3/16" rivet to fix it which means you'd also need 3/16" rivet set as well if you go the rivet route.
 
I think if that was mine I would start with the parts assembled using a needle file or dremel with a pointed tip and turn it from an 8 back into a round hole, then drill undersize 3/16 (or 5/32 if possible) and ream to 3/16" (or 5/32") to make sure you end up with a perfect hole before trying another rivet (or bolt).
 
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Removing rivets

I'm not trying to be critical with my remark. I'm looking at the pictures which show a couple bucked rivets. It appears they are being way over bucked. You may want to go back and check your work. Building a project in school has got to be a challenge.
Charlie, Tucson AZ
 
Thanks!

Wow, thanks guys with all the input!

I got that rivet removal tool, it's really good....only wish they have one for 426, the rivet in this particular problem is a 426,

I tried doing it the proper way, which I took the Mfg head out, leaving the shank and the shop head. Then I tried to punch the shank out, but I am not sure if it is because it is a -14, I went full strength and try to tap it out but no joy. Like Filon says, it might have expanded and it really don't want to come out. That's when I tried to drill deeper and deeper, eventually to to point where I have to drill it all the way, only to realized it made its own path to the other end.

Thanks for the advice on drilling out rivet, will try that next time.

Still waiting for Van's reply, but I think I am going for a NAS517 countersink screw. Like Auburntsts pointed out, I would need to get a 3/16" rivet set and I will probably have a hard time driving that rivet.

Charlie, any constructive criticism is good advice, thanks, will double check, cheers! The students are good, they can out rivet me anyday :)

Mike, PM sent, thanks!
 
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-14 too short?

Let me guess... you originally drilled this rivet out because the -14 wasn't long enough for a proper shop head? The -14s are a bit short in this location IMO.

Stan
 
How did you know that?!

Yeah, the shop head turn out a bit small, then it gets worst on the second one, third one is when the disaster strike.... I guess each time I drill it out, the hole gets bigger and it expends and fill up the extra space, leaving less for the shop head...I think
 
Agreed. Bolt is probably your best solution. Before committing to that, check with the mother ship (VANS). Make sure there are no clearance issues as well before proceeding.
 
I'll let others chime in on how to fix this.

However, it looks like your technique for drilling out rivets is incorrect. The idea is to not drill all the way through the material. My technique for drilling out 1/8 inch rivets is to use a 3/32 bit and drill into the manufactured head. Take another (older, dull) 3/32 bit, turn it around backward and stick it into the hole you just drilled in the rivet and work back and forth until you pop the manufactured head off the rivet. Now the rest of the rivet should pull out of the other side or you may need to grab the shop head with some needle nose pliers. Sometimes the rivet may get stubborn and you'll need to enlarge the hole in the shop head to 1/8 and work it with a 1/8 inch bit.

This technique does work and it works well but it takes some practice. When I built my wings I realized that I screwed up the flap braces and had to drill out every one of those 1/8" rivets.


2005-04-01.587.jpeg
2005-04-04.609.jpeg

LoL "your technique". It's always interesting to meet the author of AC 43.13-1B. There seems to be quite a few of you on VAF
 
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