Yeah, it's Ugly....But is it OK?

TomAniello · #1 02-23-2008, 01:08 PM

I have to admit that I just hate to drill out rivets. As a newbie who really likes using the pneumatic rivet squeezer, every once in a while I do need to pull out the gun and a bucking bar. No problem with flush rivets, but my universal rivet technique still leaves something to be desired.

Question for the forum: Should I drill these out and try again, or build on? Thanks for the straight advice.

B737NG · #2 02-23-2008, 02:10 PM

During my pre-cover inspection I was written up for 2 rivets in the wing like the ones in your picture. I sent a picture of the rivets to Vans.

This was their response:

EXCERPT from Alcoa Aluminum Rivet Book, dated 1984.
?The standards to which driven rivets should conform are frequently uncertain. In addition to dimensions and perfection of shape,
inspection is concerned with whether the drive head is coaxial with the shank (not ?clinched?) and whether there is excessive
cracking of the heads. It has been determined that even badly cracked heads are satisfactory from the standpoint of static strength,
fatigue strength and resistance to corrosion. (Poorly set and cracked) rivet heads were tested in tension to determine how well
formed a head has to be in order to develop full strength. The tensile strengths of all the rivets were within five per cent of the
strongest. The test indicated that minor deviations from the theoretically desired shape of head are not cause for concern or
replacement. The second rivet that is driven in any one hole likely to be more defective than the first because the hole is enlarged
and rivet will be more likely to buckle and form an imperfect head.

I did not replace my two rivets - Feel free to make your own decision.

Paul

kevinh · #3 02-23-2008, 03:10 PM

You mentioned you are new - If you do decide to drill out:

* Use an automatic punch in the hole on the head
* Use a #32 drill bit
* When you put your #30 punch in the hole, you can pop the shop head off easily

No expanded holes that way

AntiGravity · #4 02-23-2008, 03:21 PM

Well, I have to say, I've become a bit of a master at drilling out rivets. The technique I use is to get a good center (automatic punch or whatever, then drill straight through with a #40 or smaller drill. This seems to relieve the pressure on the sides of the rivet gripping the hole. Then I drill down with a #30 or slightly smaller just enough to enable me to pop the head off using a 1/8" punch. Then back the rivet up with a block of wood, socket, whatever (I prefer wood; less damage and marring to the structure) and punch it out using the 1/8" punch. I've found that although it takes longer to double-drill, it is easier to punch the rivet out and I rarely screw up the hole this way. Also, if the smaller 'thru'-hole is slightly off center you run less risk of ovalling the hole and causing a bigger problem. While this method serves *me* well; ymmv, use this method at your own risk.

rfinch · #5 02-23-2008, 04:54 PM

See this thread with a similar question. I would think you do not need to drill it out unless you are confident you can do so without enlarging the hole.

Jeff R · #6 02-23-2008, 05:53 PM

If you are concerned about what other people who might see the rivet will think about your work more than the actual strength of the joint, then drill it out. I think a lot of people want their work to appear to be near perfect, so they will drill out a rivet that is structurally sound, failing to realize their their more-perfect looking replacement is actually weaker. Not that the replacement, prettier rivet, though weaker, will not still be strurturelly sound, too.

mike647m · #7 02-23-2008, 06:28 PM

Try putting a piece of masking tape on the universal head before riveting.

Hal-san · #8 02-23-2008, 07:56 PM

Quote:

Originally Posted by mike647m

Try putting a piece of masking tape on the universal head before riveting.

Yep Mike, that works for me. I saw it on the show "How its Made" when they were showing the building of an aircraft.

az_gila · #9 02-23-2008, 08:09 PM

...to ask yourself....

Would you fly on a Boeing if it's rivets looked like that?

gil A

lorne green · #10 02-23-2008, 09:24 PM

Quote:

Originally Posted by az_gila

...to ask yourself....

Would you fly on a Boeing if it's rivets looked like that?

gil A

Well, I agree with Gill's comment. By the way, you WILL get very good at drilling out errant rivets. So take 3 minutes, get a fresh #30 drill bit, drill it out, punch it out and re-rivet. It really doesn't look that bad...but it could be better. You posted this for some constructive comments. Sounds like you weren't comfortable with this rivet. Well, is one rivet going to cause you to fall from the sky? No, no it won't. But I think it will give you piece of mind knowing that you did it right. We take on a lot when we commit to a project of this magnitude. It's one rivet then another then...the extra effort is worth it!