Removing flush head rivets

Jeff R · #1 03-23-2008, 12:24 PM

Removing flush head rivets has not been a skill I have mastered. Fortunately, most of my riveting of such rivets has been pretty good and I have not needed to remove very many but, when I did have to remove some, I too frequently botched it. I am pretty decent at removing regular rivets, but flush head rivets are something else. Can someone explain the best way to remove them? I ask this as I made a mistake and find I have to remove a bunch of rivets.

As a side note, have any of you become, well, sort of mentally attached to your airplane as you build it? I may be sitting inside with the family and find that my airplane is "calling me". If I don't spend time with it, it (she?) will get upset at me and cause me to make a mistake, thus requring me to spend more time with it (her). I have taken the last 3 weeks off to work on the plane and get back into flying, and the building has been going well. Today, I "told" the airplane I was going back to work tomorrow. Next thing I know, I find out I need to remove a few dozen, highly visible flush rivets, remove and replace a part, and re-rivet it all back together. Did I make my plane mad at me? Now, of course, this is crazy and I don't believe my plane is alive, but sometimes it sure seems like something strange is going on. Maybe it is just me bumming out about having to start work again and losing concentration. Just wondering if some of you have ever been "called" by your airplane to come on work on it?

painless · #2 03-23-2008, 12:53 PM

Hi Jeff:

I am sure others will chime in with various techniques, but I will submit mine.

You willl notice that there is a very slight dimple in each flush rivet head. What I did was take a new #40 drill bit and drill into that dimple very carefully to a depth of about the height of the manufactured rivet head. Then I would take a center punch and stick it into the hole and use that to snap off the manufactured head. Use a punch that fits that hole you drilled fairly close. Then use the same center punch to punch out the shop head through the rivet hole. Worked well for me and did not enlarge the hole at all.

As to your airplane calling you....Just wait until you are flying it!!

Regards,

Rick S. · #3 03-23-2008, 01:11 PM

Not that I have ever set a bad rivet

but I hear that a #42 bit is good, little smaller than the #40. Also use a 3/32 punch to snap off the head. Go slow so the bit doesn't travel on the initial startup of the drill. Drill deep enough to get a good set with the punch to allow the head to snap off. I actually drilled out someone elses bad rivet once

and before I stopped the head popped off onto the drill bit and the shank just squrited out the other side..no punch needed for that at all.

N941WR · #4 03-23-2008, 01:29 PM

Jeff,

Check this thread.

There is a lot of good info in the Building Tips section, ya just gotta search for it.

Mike S · #5 03-23-2008, 01:42 PM

I use a drill bit of the same size as the rivet hole---#30, 40 etc. to drill the head, and the back end of another drill bit of the same size to pop the rivet head off.

Center punches often have too much taper in them to get a good grip on the rivet head.

A pin punch will work fine, if it is the correct size.

Good luck

rzbill · #6 03-23-2008, 06:56 PM

For critical spots, or if I am out of practice, I like to start the rivet removal process with a drill bit that is smaller than the body of the rivet. For AD4's, I usually start with a #40. For the AD3's, I grab a 1/16" bit out of my drill set.

Anyway, you can start drilling the head and if the hole wanders, angle the drill A LOT to make the bit re-center. Short drill burst and then check. This technique can get you a pilot hole in the middle of the rivet body evey time as long as you agressively steer the bit and get it centered before you run out of factory head length. Come back with the right body diameter drill just deep enough to make a "bore" for a pin punch or "backwards drill shank" to pop off the head. Center punch/ pin punch/ or auto punch the rivet body out.

I have used this technique to CLEANLY remove AD4 rivets up to 1/2" long. To remove these, you have to remove some metal from the center of the rivet body before it will loosen up enough to be banged out with a pin punch.

The technique works. I am well into the fuselage and so far have used about 6 oops rivet on the whole project.

az_gila · #7 03-23-2008, 08:02 PM

Pictorial view for a safe removal method on my web site....

http://home.earthlink.net/~gilalex/Rivet/

A picture vew of what rzbill described....

gil A

Jeff R · #8 03-23-2008, 08:06 PM

Thanks all. I am now nearly an expert. Using a smaller bit to drill into the center of the rivet (1/16th inch for the -3 rivets), followed by using a #30 bit to then shear off the head, worked really well. My problem before was I used a #40 bit, which was difficult to keep centered, and which enlarged the hole and often not shear off the head. This new way worked like a champ.

RScott · #9 03-23-2008, 08:51 PM

If the metal on the shop head side is thin, using a punch to remove the shop head can bend the metal. I like these pliers from Avery: https://www.averytools.com/p-830-pai...ty-cutter.aspx

They can go flush against the metal and grip the shop head really well. Then you just pull the rivet out, laying one side of the pliers against the metal to hold it down. You can take some side cutters and grind the side down flat to accomplish the same thing, but these work better.

You want to come drill out 470 rivets for me? I have no problem with the 426's, but often have problems with the 470's. Can't drive them as well, either.