What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Damaged manufactured rivet head. Replace?

I

inktomi

Well Known Member
Sponsor
Hi,

Would you replace this rivet? The head is damaged by my not holding the gun against it hard enough, and so it moved while setting the rivet. Otherwise, it seems to be set well.

I was at a build assist shop and they encouraged me to carefully consider the benefit of drilling out a rivet before doing so. The hole can be damaged by the drill, but it’s also slightly oversized now because of the rivet having expanded in the hole too.

I’m working on my tail kit, so I have not drilled out lots of rivets yet, but I’m fairly confident at it.

So what would you do? Replace? Or leave it since we’re not building timepieces and it’s probably strong enough for the job? Even if it were to crack, this part would be held in place by the skin and the second rivet.
 

Attachments

  • IMG_3229.jpeg
    IMG_3229.jpeg
    1.5 MB · Views: 332
  • IMG_3230.jpeg
    IMG_3230.jpeg
    1.4 MB · Views: 327
Drill it out...and...

(Warning -- Religious Argument Forthcoming -- get the popcorn out.)

Personally, I would do everything in my power to NOT buck universal (AN470) rivets. If you don't have the arm strength to use the "Main squeeze" or similar, suggest that you invest in a CP-214 (or clone) pneumatic squeezer and all the available yoke styles and sizes.

Bucking rivets is a violent operation, and when done incorrectly, can damage the substrate material. I suspect, as do others, that the recent Service Bulletin on the Horizontal Stab Hinges was in part caused by builder technique (bucked rivets).
 
I would love to squeeze it, I like the ease, and even the heads end up looking perfect when squeezed instead of slightly polished by the rivet gun. I don’t have a yoke that will fit down into this area though, so my only option is bucking.

I do think if I put some washers into the yoke under the die I could reach this with the squeezer. I’ll give that a try.
 
Last edited:
Drill it out.

For 1/8” rivets I’ve had good luck doing:
- #30 drill bit, drilling enough to then pop off the rivet head using the shank of another #30 bit. Do not drill into the base material.
- #40 drill bit, drilling through the center of the rivet shank.
- A good wet of pliers to then pull out the manufactured head and what is left of the shank.

Doing this the original rivet hole rarely gets damaged.

One suggestion, put ~3 layers of standard masking tape over the round head rivet set. This will eliminate all but the most egregious riveting mistakes. Replace the tape when needed (every third or so rivet).

Carl
 
Funny how this site changes. If I may, then I'll go back into my corner.
1. Ask yourself, can I drill it without damaging. If the answer isn't "yes", try this.
2. Punch the dot. Yes, we can all guide a drill bit perfectly. We also can drive like Dale, so why do we carry insurance? Punch the dot with a bucking bar behind.
3. Grab a bit 10 sizes smaller than the parent hole. I prefer even smaller. Drill. If you go through, just don't hit anything.
4. Grab a bit one size smaller than the hole with a drill stop. Still driving without insurance? Put the stop on the bit and adjust it so no matter what, the bit can't go past the head. Drill it.
5. Take the bit out and use the opposite end to snap the head off in one quick motion.
6. Using a pair of wire cutters, twist the shop head. Usually it comes right out. If not, proceed to the next step.
7. Grab a pin punch and ask someone to hold a bar behind. Better still. You should have a set of home made bars with a hole that fits over the shop head. Shameless plug for a Kitplanes Tip I wrote long ago. Tap, tap, tap and the shop head pops out with no bent parts.
Ok. Back to my corner
 
I find a small center drill can be placed in the AD dimple on the manufactured head and a quick one second burst of drilling will create a great pilot hole. Drill the pilot hole with a slightly undersized drill bit. I usually drill concentrically right into the rivet shaft using this technique. Rivets will actually just fall out if you perfectly drill the rivet shaft to just short of material depth.
 
rsultzbach said:
I find a small center drill can be placed in the AD dimple on the manufactured head and a quick one second burst of drilling will create a great pilot hole. Drill the pilot hole with a slightly undersized drill bit. I usually drill concentrically right into the rivet shaft using this technique. Rivets will actually just fall out if you perfectly drill the rivet shaft to just short of material depth.
Click to expand...
Second the center drill. They are really pointy and stay perfectly where you center punch. No more wandering drill bits.
 
Lots of good input here on HOW to drill it out, and several opinions sayiong that you should. What I am curious about is what Van’s says? Even if you decide to take teh advice of all us random people on the internet, just for grins, why not send the pictures to Van’s and see what they say? Then report back. We all become better when we get expert guidance - whether it agrees with our opinions or not.
 
My guess is that having one rivet like that wont make any difference - the problem with this approach is that it may become a habit …
 
I’d replace that one. Like others here I tend to drill smaller but only head depth with tape around the offending rivet. Use the shank of the drill to pop the manufactured head off….make a solid base behind the shop head…use a smaller than 30 size pin punch to tap out the rivet with the solid base behind it. Pop a new rivet in and set it. You have one shop head there that looks under set? It may be ok diameter wise with your gauge but it’s the height that matters….. at .050 to .070 using the tail of your micrometer. I’m guessing that looks more like .090 and the other rivet shop head within spec.
 
A lot of advice to drill it out. I’ve had a number of rivets that ended up like this, and the response from Van’s has so far been 100% in the leave them alone camp. Specific location can matter, so best to ask them, but don’t be shocked if they tell you to build on. I know a lot of builders just can’t stand having any imperfect rivets hidden in their planes. To each their own, but leaving a “bad” rivet doesn’t automatically make you a builder who doesn’t care and will let any garbage pass the QA check. Sometimes it’s just a bummer, structurally sound, and is no reflection on how much you care about safety or quality.

(maybe an artifact of the picture, but do check that top rivet - looks like it is a little shy on the set)
 
inktomi said:
Hi,

Would you replace this rivet? The head is damaged by my not holding the gun against it hard enough, and so it moved while setting the rivet. Otherwise, it seems to be set well.

I was at a build assist shop and they encouraged me to carefully consider the benefit of drilling out a rivet before doing so. The hole can be damaged by the drill, but it’s also slightly oversized now because of the rivet having expanded in the hole too.

I’m working on my tail kit, so I have not drilled out lots of rivets yet, but I’m fairly confident at it.

So what would you do? Replace? Or leave it since we’re not building timepieces and it’s probably strong enough for the job? Even if it were to crack, this part would be held in place by the skin and the second rivet.
Click to expand...
No! But my luck varies FIXIT
 
JonJay said:
If you’re going to remove it, this tool makes a big difference. However, setting the tool for proper depth and making sure it “fits” properly over a smushed rivet can prove difficult.
I have removed thousands of rivets and still screw them up from time to time….
Click to expand...
I have this tool and have used it several times. It does make a difference but one still needs to be VERY aware of the depth the drill goes into the rivet. My advice: leave it. The bulk of the machine head is still there and intact. You could possibly make more of a mess drilling it out. IMHO......

Here are some pictures to make you feel better. These were from the Weeks Fantasy of Flight restoration shop (special privilege to have been in there!!) and they were restoring a wing, drilling out ALL of the round-head rivets and replacing the entire skin. Notice on the left side of the picture where the skin has been removed the rivet HEADS have been removed but the shank of the rivets remain in place. You can see a restored wing just behind all that. Next picture is the new skin in place getting ready for the rivet gun!. These guys were GOOD but have worked there for decades. You would not believe the amount of things he has in store room after store room after store room after...... :oops:
 

Attachments

  • Jan 30 190.JPG
    Jan 30 190.JPG
    3.3 MB · Views: 47
  • Jan 30 188.JPG
    Jan 30 188.JPG
    1.8 MB · Views: 50
You must log in or register to reply here.
Back
Top