Stupid question?

Brambo · #1 03-21-2006, 08:43 AM

I just started on my empennage for the RV-7 and have a question that is probably pretty stupid. Does it matter which way you put a standard rivet in? In other words, does it matter which side the shop head is on? I noticed a picture on the forum of a piece similar to what I have already done and noticed that the rivets where opposite of what I had done. I didn?t recall any direction from Van's in there manual so I'm hoping it doesn?t matter, but if it does now would be a good time to find out.

apatti · #2 03-21-2006, 08:57 AM

You aren't building a plane until you ask a stupid question.

And this one doesn't even count.

Actually, there was an article in the RVator a year or so ago about this. I can't remember who wrote it but it was someone from Van's. They said they were surprised that they had never thought of the issue before. The conclusion they came to was "no, it doesn't matter". Whichever direction seems to be the easiest for you when setting it. If I have a choice, I try to place the manufactured head where people will see it so I don't get comments on my riveting technique.

As we say in production, "ship it"!

ge9a · #3 03-21-2006, 08:58 AM

I believe the rule of thumb is to put the shop head (the head formed with the bucking bar or squeezer) on the side with the thicker material.

If I have a choice, and if both pieces are close to the same thickness, I generally put the shop head on the side that I probably won't see once the plane is assembled.

Greg

mlw450802 · #4 03-21-2006, 09:07 AM

Quote:

Originally Posted by ge9a

I believe the rule of thumb is to put the shop head (the head formed with the bucking bar or squeezer) on the side with the thicker material.

If I have a choice, and if both pieces are close to the same thickness, I generally put the shop head on the side that I probably won't see once the plane is assembled.

Greg

What Greg said!
You can do a quick little experiment using some drastically different thickness material like a piece of 1/8 inch angle and a 0.016 sheet stock. Make a legitimate rivet pattern and experiment with the manufactured head and shop heads on each side. You'll find that often when the shop head is on the thin side, the swelling rivet will distort the thin sheet, making puckers. When riveted the other way around the sheet stays nice and flat to the angle.

-mike

Brambo · #5 03-21-2006, 10:06 AM

Thanks all, I feel better now.

Jekyll · #6 03-21-2006, 11:43 AM

Sort of a decision tree:

a. What does the design need ie: flush rivets on exterior surface or interference with other structure.
b. Access is king, does it only have 1 path to success or 2?
c. Shop head on thicker material
d. Asthetics

Satisfy A first, then B, decide on the merits of C and then go with the eye if A-C are satisfied.

Jekyll

LettersFromFlyoverCountry · #7 03-21-2006, 05:08 PM

Quote:

Originally Posted by apatti

They said they were surprised that they had never thought of the issue before. The conclusion they came to was "no, it doesn't matter". Whichever direction seems to be the easiest for you when setting it. If I have a choice, I try to place the manufactured head where people will see it so I don't get comments on my riveting technique.

I remember reading that in RVator and thinking, "that's odd, you address the subject in your instructions." Of course it notes the rule of thumb and adds that they didn't think it made any difference, but the RVator article made it sound like they never heard the question before.

The answer, from my perspective is, "yes, it does matter, but not for the reasons you might think."

I'll give you an example. When I riveted the rib to the rear spar, I put the manufactured head on the rib and bucked the rear spar.

And that worked really great until I screwed up a rivet. Impossible to drill it out (especially if the rib has already been riveted to the forward spar and there's a neighbor rib there too. You can't get a drill in to drill out the head.

So now my rule of thumb is....if I have to drill out this rivet...what's the best way to come at it from? And that's where the manufactured head goes.

jcoloccia · #8 03-21-2006, 05:16 PM

When you get to rivetting the hinge brackets onto HS and VS spars, you may want to put the manufactured head on the bracket side, NOT the spar flange side. If you do it this way, you'll have a little more clearance when you go to rivet the skins to the spar. It'll make more sense when you have the pieces in front of you and can imagine sneaking a squeezer between the bracket->spar rivets and the shop head end of the skin->spar rivets. Some of them line up JUST right to be a royal PITA.

bullojm1 · #9 03-21-2006, 06:42 PM

I dug this up in the Military Specifications :

3.3.3.1 Head direction. Unless specified on the engineering drawings or specification, the manufactured head of the rivet shall be located on exterior surfaces.

But like other people have mentioned, it isnt always the best or easier way in all circumstances.

- Mike Bullock
http://rvplane.com
RV-7, Wings on the way....