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A few newbie riveting questions

H

Hink

Member
I'm new to the world of bucking rivets. I have completed the tool box practice kit and half of the other and have a few questions.

Are both sides of the hole de-burred?

When using Avery's rivet gauges, which is more important, diameter of the shop end head, or depth? When I get the correct diameter the shop end is a little to long, when driven more the head diameter gets to big for the gauge to fit.

When bucking rivets on dimpled skins how can depth of the shop end be measured?

I noticed when cleco'ing the clecos leave small scratches is this normal?

Lastly, once bucked the A end is the rivets appear discolored or marred, are they later buffed or cleaned prior to painting?

Sorry if some of these sound dumb, just want to get this thing right.

Scott
 
1 - yes
2 - diameter
3 - to the "top" of the dimple
4 - yep, build on
5 - A="Manufactured head", yep, paint covers everything but the worst craftsmanship. Totally normal.

6 - Find a local tech counselor :).
 
Thanks for the info. I was planning on having someone look over my work once I near completion on the vertical stab. Is this a good place, or is another better?

Also, does anyone know of a tech counselor in the Canton, GA area with RV experience? I looked in Van's book at OSH and did not see any -10 builders in the area.

Thanks,
Scott
 
Check the instructions on those Avery guages...

It's been a while, but I seem to recall that you don't want the rivet to fit in the hole (barely) AND you don't want it to slide under the notch in the end of the gauge. From the way you described it, it sounds as if you were trying to do something different.
 
Scott,

You'll also find many discussions on the list about getting the correct length rivet. The semi-non-official report from people is that rivets commonly come in 0.5 increments. You can get a cutter and make the length's perfect, or as suggested aim for the diameter of the shop head.

An example I'll cite, on my wings, the plans called for a AN426-3-3 rivet to attach the gap farings to the wings. So I smashed one in there. It just didn't look right, hard to explain, but you'll understand after several more rivets. Also I didn't have enough 3-3 rivets but I had a ton of 3-3.5. So I hit one of those in, that looked better, but maybe a bit tall.

The 3-3 probably would have worked, I got the diameter correct, but no way the length was right. However, this is just a faring, there will be no major stress on it, so the rivet is really just to keep the thing from falling off. :) I used the 3-3.5 since I had them and I made sure they wouldn't bind on the flap or alieron. Now if you go too tall, then the rivet can "tip-over" when you start to drive it. The shank bends rather than squashes.

As for cleco scratches, you can get little rubber boots for the cleco's, but if you are painting, don't worry about it. If you're polishing, well ...

Use your head and think things through and you'll be just fine. And don't worry, if you make a mistake you'll fit right in here. :D

Go get a scrap piece of metal and put several different rivet sizes in holes and buck them so you can see exactly what "wrong" looks like. It's amazing how quickly you can tell if a rivet it right just by eye. I still use the guage often, but most times I know as soon as I squeeze the trigger if it's going to be right or wrong.

Keep it up, you'll get there.
 
Welcome, Scott

There are two EAA chapters near you...one in Marietta and a big, active one in Lawrenceville, with quite a few builders and Tech counselors. Visit www.eaa.org and find the chapters by City and State and their meeting dates and times.

The EAA site also has a tech department with videos of most aspects of building as well.

Regards,
 
Hey Scott,

I have not clue where Canton is. How far outside of Atlanta are you?

I know two builders there.

Phil



Hink said:
Thanks for the info. I was planning on having someone look over my work once I near completion on the vertical stab. Is this a good place, or is another better?

Also, does anyone know of a tech counselor in the Canton, GA area with RV experience? I looked in Van's book at OSH and did not see any -10 builders in the area.

Thanks,
Scott
Click to expand...
 
Rob - What you describe is in line with my experiences, I can either get the hole to fit snugly over the shop end but unless driven a little more than slightly bigger than the hole it will not pass under the notch in the gauge. It's an either/or not both situation, I was wondering which was 'correct'. My biggest problem has been the 3-3 rivets that fit in dimpled material, the bulge created by the dimple makes it harder to see. The rivets don't seem to display a slight 'marshmellow' like the 4-4's. I've done a few with scraps and cannot pull them apart, but want to get this right.

Niblet - Polished looks really nice, but probably not on a -10. Reading about deburring and scratches has me a bit freaked out I just wanted to make sure those scratches are not detrimental.

Pierre - Thanks! I'll check into Marietta's chapter.

Phil - Canton is about 35 miles N of Atlanta.


Thanks again for your insight. I typically try to figure stuff out on my own, but can allready tell I'm going to have to lean on others to get this done right.

Scott
 
Last edited:
Hink said:
When using Avery's rivet gauges, which is more important, diameter of the shop end head, or depth? When I get the correct diameter the shop end is a little to long, when driven more the head diameter gets to big for the gauge to fit.
Click to expand...

Remember these dimensions are minimums. Too Tall or too fat are OK as long as both meet minimum dimensions.
 
The object of Avery's rivet gauges is that you don't want it to fit either. If the head fits into the hole, you haven't driven it enough. If it fits under the notch, you've over-driven it. Practically speaking, though, if you follow Van's callouts there will be many times when both aren't achievable because the rivets are slightly short. It's been discussed a lot before this but I list your options here so you don't have to hunt them down. 1) Use Van's callouts and compromise using the gauge as a rough guide so that the heads aren't too short or wide after driving. 2) Use a longer rivet, with increased chance of clinching the head while driving. 3) Use a longer rivet cut or filed down to the right length.

Personally, I tended to go with option 1 in most places (the skins are notorious for needing -3.75 length rivets) as I knew that structurally I was not losing much and Van has way over-designed the airframe. However, there were places I fell back on option 2 because I was just not comfortable with the shop heads I was getting. I tried option 3 and concluded that life was too short to cut thousands of rivets to the perfect size. Opinions vary, though, so go with what makes you comfortable and makes your inspectors happy.

Start getting to know people at your local airport; try to find out where the local crowd eats lunch or when/where they fly for the '$100 Hamburger'. At my airport there is a core group that does this and are happy to take along passengers (who pay for gas or lunch). Amongst such a group will be A&Ps who will be happy to advise you on your workmanship. A tech counselor is best for getting you through the home-building process but don't neglect other sources of knowledge and advice.

Finally, on the discoloration: rivets are coated in alodine which gives them that gold color. After driving, the shop head will often have an aluminum-colored circle and both it and the manufactured head will have slight smudging from the tools (which will likely be less than perfectly clean). Perfectionists will clean the shop head side and then daub them with primer but I have been told this is over-kill. The manufactured head side (at least on the skins) will either be prepped and primed before painting or will have the alodine polished off completely if the surface is to be polished. The same is true of any surface scratches caused by clecoes or rings around the rivets caused by dimple dies, countersink cages, or rivet sets. As long as there are no major imperfections and it feels smooth to the finger, move on.
 
niblettda said:
Scott,

An example I'll cite, on my wings, the plans called for a AN426-3-3 rivet to attach the gap farings to the wings. So I smashed one in there. It just didn't look right, hard to explain, but you'll understand after several more rivets. Also I didn't have enough 3-3 rivets but I had a ton of 3-3.5. So I hit one of those in, that looked better, but maybe a bit tall.

The 3-3 probably would have worked, I got the diameter correct, but no way the length was right. However, this is just a faring, there will be no major stress on it, so the rivet is really just to keep the thing from falling off. :) I used the 3-3.5 since I had them and I made sure they wouldn't bind on the flap or alieron. Now if you go too tall, then the rivet can "tip-over" when you start to drive it. The shank bends rather than squashes.
Click to expand...

I did exactly the same thing a few weeks ago. Give it some time, and you'll very quickly be able to look at a rivet visually with no guage and tell if it's OK. After a few thousand rivets you'll get good at just feeling the shop head with a fingertip in a place where you can't look at it, and determine if it's OK or not just by feel.
 
I did quite q bit on a 7A then sold the project. I now have a project (non-RV)
under construction near Cumming, GA. Shoot me an email if you are interested in getting together.

Derrell
[email protected]
 
this is a common question on sizing, here is my post from a while back:
____________________________________________
if you have a set of calipers you can measure and compare to the actual standards instead of a gauge that doesn't specify the limits, only the best case.

you can look up the standards here: http://www.engineersedge.com/rivet_application.htm

for example, 1/8 driven head can be .050 to .070 tall, with a minimum of .163 in diameter.

MY avery 1/8 gauge is .062 for height, and .190 for diameter. so if it slips around the shop head diemeter or is just tight, you're ok. if you gauge over or under for height by just a little bit you are ok as well.

the standards for a 3/32 rivet are: .122 minimum diameter and .038 - .050 for height.

MY 3/32 avery gauge is .139 for diameter and .046 for height
________________________________________


best to double check your gauges to the specs, you should have a caliper if you are going to build an airplane.

short answer- if you have avery gauges, and they haven't changed from when i got mine 1.5 years ago, as long as the shop head is close to the gauge, either under or over size, you will be ok. there have been some studies that show it is better to squish to much (but only a little) rather than under squish a rivet. of course the preference is for within specs, but don't go drilling out rivets because they are .005 to wide or flat. get the next one better and get on with the build.


edit- link from another thread, you might read http://www.vansairforce.com/community/showthread.php?t=39810&highlight=head
 
Last edited:
flion said:
The object of Avery's rivet gauges is that you don't want it to fit either. If the head fits into the hole, you haven't driven it enough. If it fits under the notch, you've over-driven it.
Click to expand...


based on my actual measurements of MY avery gauges, this statement is FALSE.

see my post right above, the avery gauges I HAVE are in the middle of the allowed range for height, and the diameter is fine if the gauge goes on with a tight fit.
 
Hmm, yes, I phrased that badly. Danny is, of course, correct. However, I have found that shop heads which are too short and have too small diameter for the gauge generally indicate that I should have used a longer rivet to begin with. I am happiest with my work when both diameter and height are slightly too big for the gauges. Really, though, it's not that hard to drive acceptable rivets with a little practice.
 
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