Failed my Airframe Oral/Practical (Rivets)

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gcd89

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Greg D.
Need help with riveting. I don't know what went wrong, but from what I can gather (after scanning some youtube videos) I probably wasn't holding the bucking bar properly or it walked on me. It's hard to remember looking back on it. Does anyone have tips or some kind of video on the fully proper way, or maybe some kind of tutorial on common rookie mistakes and how correct/avoid them? Is it something that takes lots of practice, or can I get it right the first time, granted I avoid (insert common mistake)?

Thanks for the help.
 
gcd89 said:
Need help with riveting. I don't know what went wrong, but from what I can gather (after scanning some youtube videos) I probably wasn't holding the bucking bar properly or it walked on me. It's hard to remember looking back on it. Does anyone have tips or some kind of video on the fully proper way, or maybe some kind of tutorial on common rookie mistakes and how correct/avoid them? Is it something that takes lots of practice, or can I get it right the first time, granted I avoid (insert common mistake)?

Thanks for the help.
Click to expand...

The AC 43,13 is the better how to on rivets, but practice is how to be consistent.
 
Weren't you told why you failed? That is, what you did wrong?

Personally, If you don't know why you failed, I don't think looking at random videos of "the proper way" will help if you don't know what you did wrong.

(I'm an A&P student, and am not there yet, so I can't comment too much)
 
ajstoner21 said:
Weren't you told why you failed? That is, what you did wrong?

Personally, If you don't know why you failed, I don't think looking at random videos of "the proper way" will help if you don't know what you did wrong.

(I'm an A&P student, and am not there yet, so I can't comment too much)
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Well, the DME basically said "You shop ends are to thick, you smiley faced one, and your flush rivets aren't flush".

They tell you why you failed, but they don't explain WHAT exactly you did wrong. He didn't tell me why my rivets weren't flush
 
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ajstoner21 said:
Interesting! Good luck figuring out what went wrong!
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Well a few Youtube videos did help.

"Make sure everything is perpendicular"...the kind of stuff you may overlook
 
gcd89 said:
Well, the DME basically said "You shop ends are to thick, you smiley faced one, and your flush rivets aren't flush".

They tell you why you failed, but they don't explain WHAT exactly you did wrong. He didn't tell me why my rivets weren't flush
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Well, first things first, you put a smile on a rivet during any test you fail, because you allowed the rivet gun to slip. Second the buck tail must be 1.5 times the diameter and 1.5 times the hight of the original rivet diameter.

The flush rivets are easy, you set the counter sink correctly or nothing will be flush. set the countersink, test it, adjust it, test it, set it again, test it until the rivet sets correctly in the hole before you buck it.

Riveting is easy, bend allowance is hard, try bending a "U" channel that will lie correctly in another "U" channel, and make the top edges the same hight.
 
I found this useful. attached from AC 43.13-1B chg 1
You have to look at the ones you did wrong closely, and decide what caused the problem. Decide how to fix and then keep riveting until you no longer do that thing.

"You shop ends are to thick,
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I would have to guess that either
a) you cut the rivet too long to begin with, or you cut it to the right length but did not set it enough. See the attached diagram on how they should end up.

you smiley faced one,
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there isn't an a+p out there that has not smiled one, but you should be able to learn how to grip the tool securely and control its motion.....what pressure is the regulator set at? Too high and it will be like a 50cal machine gun.

and your flush rivets aren't flush".
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You need to properly size the rivet and dimple/countersink before getting near the rivet gun.
If the rivet sticks up above the sheet before setting it, you are unlikely to mash it flush using the rivet gun.

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2004.pdf
 

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Start with the right length.

Bucking bar doesn't move - keep it square. Take your time getting in to position.

Don't try to drive it all in one shot. Give it a quick shot, stop, guess how much is left, a couple more hits and check again.

Practice, practice, practice.
 
Hey, how are you holding your rivet pieces? I assume no one has given you a wing yet, and you are working on a 6x6" piece of scrap. If you are trying to prop it up, and both rivet and buck, that is way too much for your first time. Put it in a vice and get someone else to hold the bucking bar til you get good at the driving.
 
Let'sgoflying! said:
a) you cut the rivet too long to begin with, or you cut it to the right length but did not set it enough. See the attached diagram on how they should end up.
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I didn't have to cut (?) them. I was given 4 rivets and he said "drill the holes, rivet this scrap metal".


there isn't an a+p out there that has not smiled one, but you should be able to learn how to grip the tool securely and control its motion.....what pressure is the regulator set at? Too high and it will be like a 50cal machine gun.
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This gun didn't have a regulator. He even said before hand "This gun is a little different than the one you got at school. If you want less pressure, pull the trigger less"


You need to properly size the rivet and dimple/countersink before getting near the rivet gun.
If the rivet sticks up above the sheet before setting it, you are unlikely to mash it flush using the rivet gun.
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What do you mean by "sizing the rivet"? I didn't pick the rivet, drill bit or anything. He gave me all the rivets, and a drill bit and said "the project isn't laying out the rivets or schoosing the correct ones. Just your ability to actually install them".
 
Let'sgoflying! said:
Hey, how are you holding your rivet pieces? I assume no one has given you a wing yet, and you are working on a 6x6" piece of scrap. If you are trying to prop it up, and both rivet and buck, that is way too much for your first time. Put it in a vice and get someone else to hold the bucking bar til you get good at the driving.
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I just put the working piece in a vice.

The thing is, in school, I built an ENTIRE wing section (bent the metal, cut the sheet, layed out the rivets, etc), but that time, it didn't need to be "airworthy" to pass.
 
The thing is, in school, I built an ENTIRE wing section (bent the metal, cut the sheet, layed out the rivets, etc), but that time, it didn't need to be "airworthy" to pass.
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Could it be you were taught poorly and now have to unlearn all that? We'll help!
 
I didn't have to cut (?) them. I was given 4 rivets and he said "drill the holes, rivet this scrap metal".
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See the very first image in the pdf I posted above "Rivets" most rivets come over-long and you have to use a rivet cutter to ensure you are driving a tail that protrudes 1.5xD from the material. If it was way too long, it won't buck down to the correct height. I would at least eyeball the ones he is giving you to make sure you have a chance of success. Reject them (in a test scenario you will have to do this diplomatically!)
if they aren't close to 1.5D. Tell him why (quote the AC if you need to!) and ask for correct lengths.

This gun didn't have a regulator. He even said before hand "This gun is a little different than the one you got at school. If you want less pressure, pull the trigger less"
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It's probably just that you need to grip the gun more firmly or securely. Try to have the workpiece held horizontally (ie like a table surface) so that you are over top of it looking down. I think trying to rivet a vertical surface with the gun horizonally might lead to more slippage until you are good at it. I did have an unregulated gun hooked up to a 120psi compressor once - wow. No way to get a good rivet.


What do you mean by "sizing the rivet"? I didn't pick the rivet, drill bit or anything. He gave me all the rivets, and a drill bit and said "the project isn't laying out the rivets or schoosing the correct ones. Just your ability to actually install them".
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He could have given you all correct size parts and tools however I would eyeball everything and make sure it is going to work.
Do you have a supply of rivets and sheet to mess with? What I was talking about is that if a hole has not been countersunk deeply enough, the cs rivet will sit up too high on the metal and never seat properly. That does sound what you described. I think you said the "flush rivets are not flush". Can you send a photo?
 
Let'sgoflying! said:
Could it be you were taught poorly and now have to unlearn all that? We'll help!
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This is a distinct possibility. I mean, I could type MULTIPLE PARAGRAPHS on how terrible my school was. But a summary: I had FIFTY people in my class and ZERO one-on-one instruction when it came to practical projects and education. One of my projects was to partially disassemble an electric fuel pump to inspect the filter....in school I NEVER EVEN SAW one of those! I had to find it and take it apart on my own. I also never learned how to measure cable tension, which I also passed miraculously. Honestly, it's a miracle I managed to get my Powerplant rating.

FWIW, I also failed three oral sections (wood, hydraulics, fuel systems), but I can go back and drill that into my head with memorization and research.
 
Keep at it, Greg - I am sure you will persist and succeed!
Says something for the old method of learning under the mentorship of an 'old hand'.
Good luck!
 
How are these schools still in business and not being shut down? This isnt the first time I've heard of a horrible 147 school....
 
Let'sgoflying! said:
See the very first image in the pdf I posted above "Rivets" most rivets come over-long and you have to use a rivet cutter to ensure you are driving a tail that protrudes 1.5xD from the material. If it was way too long, it won't buck down to the correct height. I would at least eyeball the ones he is giving you to make sure you have a chance of success. Reject them (in a test scenario you will have to do this diplomatically!)
if they aren't close to 1.5D. Tell him why (quote the AC if you need to!) and ask for correct lengths.
Click to expand...

Wait, the unbucked rivet is supposed to be 1.5d? Seriously, I'd never heard of this "cutting rivets" thing in school.



It's probably just that you need to grip the gun more firmly or securely. Try to have the workpiece held horizontally (ie like a table surface) so that you are over top of it looking down. I think trying to rivet a vertical surface with the gun horizonally might lead to more slippage until you are good at it. I did have an unregulated gun hooked up to a 120psi compressor once - wow. No way to get a good rivet.
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Yeah, I'm tihnking I was just holding the gun wrong or whatever...it probably just walked on me...



He could have given you all correct size parts and tools however I would eyeball everything and make sure it is going to work.
Do you have a supply of rivets and sheet to mess with? What I was talking about is that if a hole has not been countersunk deeply enough, the cs rivet will sit up too high on the metal and never seat properly. That does sound what you described. I think you said the "flush rivets are not flush". Can you send a photo?
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Unfortunatly, I don't have access to sheet or rivets....I'm thinking going to my school to get some additional help...thing is my (former) school is SUCH a pain to deal with and the people in the hangar are dicks...

As for the cs rivets, they were sitting flush when I put them in the holes, but were a little pushed up after I riveted them...I can't get a photo, I wasn't aloud to have a phone during the exam.:dunno:
 
ajstoner21 said:
How are these schools still in business and not being shut down? This isnt the first time I've heard of a horrible 147 school....
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Good recruiters. Most of the people I encountered were wannabe auto mechanics. They had no idea about aviation, airplanes, the FAA, etc. The recruiters were smooth talkers, that's for sure. Especially when they start saying "The average A&P makes $xxxxx right out of school".

Also, it was $37,000. 48 if you signed up for the avionics course. 50 people in my class alone. New class started every 4 month. There was 2 schools.

37,000 x 50 students x 3 classes starting per year x 2 schools= $11.1 mil annually.
 
Out of curiosity, what type and diameter rivets were you asked to buck?
 
kontiki said:
Out of curiosity, what type and diameter rivets were you asked to buck?
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Didn't tell me. He simply handed me the rivets and said "You don't need to pick them out or lay out anything, just drive these"
 
Out of curiosity, what type and diameter rivets were you asked to buck?
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The only reason I ask is to see if he might have thrown you a curve and given you DD rivets or something.
 
gcd89 said:
Good recruiters. Most of the people I encountered were wannabe auto mechanics. They had no idea about aviation, airplanes, the FAA, etc. The recruiters were smooth talkers, that's for sure. Especially when they start saying "The average A&P makes $xxxxx right out of school".

Also, it was $37,000. 48 if you signed up for the avionics course. 50 people in my class alone. New class started every 4 month. There was 2 schools.

37,000 x 50 students x 3 classes starting per year x 2 schools= $11.1 mil annually.
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Man. I must be getting pretty darn lucky.

My school has 25 people in my clsss. And I'll be with the same 25 people for 3 years (at night). Each semester is roughly $500, and we have three semesters a year (spring, summer, fall).

So, its about $5,000 -$6000 TOTAL for my program for everything; tools, books, tuition, etc.
 
ajstoner21 said:
Man. I must be getting pretty darn lucky.

My school has 25 people in my clsss. And I'll be with the same 25 people for 3 years (at night). Each semester is roughly $500, and we have three semesters a year (spring, summer, fall).

So, its about $5,000 -$6000 TOTAL for my program for everything; tools, books, tuition, etc.
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3 years?!? My school was 18 months.
 
Greg,

Did you not know some of your rivets were not set correctly? If I had smiley faced a rivet or the shop end was malformed, I would have drilled them out and redid them or at least pointed out the ones that needed to be reworked to the DME. I can't believe the DME wouldn't have allowed this especially since you had to use an unfamiliar rivet gun with no regulator. How could you not know a flush rivet wasn't flush and why? Did you countersink the material or have to dimple it? This isn't rocket science. If you didn't know your work was deficient, then he was absolutely correct in failing you. At the community college I attended, when we did projects in sheet metal, mine had to be airworthy or I stayed after class and redid it until it was airworthy. You've got to man up and take some personal responsibility. The good thing is with a little practice you should be able to get the hang of it.

I don't know why anyone would pay one of the commercial 147 schools the fees they command when a public community college gives the same training for a fraction of the cost. Yeah, some of the instructors were crap but that's true in every institution including the big commercial 147 schools. All the material is in the book(s) and if I didn't get it, I found someone to clue me in. I'd say of the 20 or so students that went through the entire course, maybe 5 at most, got their A&P certificates. I guess the other 75% thought that just sitting in class or turning in crap would be enough to get one of those high paying aerospace jobs or they were never intending to get the certificate. Some were on some government program that paid them to come to class and veg out.

Good luck on the retest. You sound like one of the 25 percent willing to work at getting it right.
 
As for the cs rivets, they were sitting flush when I put them in the holes, but were a little pushed up after I riveted them.
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ah, ok - important info. Sometime early during the driving process you allowed the bucking bar to push the rivet out of the hole. No problem, you just have to push less on the bucking bar til the rivet swells enough to bind on the hole ID. Its a technique issue that I'm sure you will resolve with practice.
Push too hard on one end you get this, push too hard with the gun and you might deform the sheet.
Also be sure to have a bucking bar of adequate mass. You might be pushing too hard with it because it is too light.
 
gcd89 said:
Wait, the unbucked rivet is supposed to be 1.5d? Seriously, I'd never heard of this "cutting rivets" thing in school.
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1.5 diameters sticking out the back (you add the thickness of the material being riveted).

A LITTLE longer is OK, but not shorter. And not a lot longer.
 
I guess one key item here is that you don't know why he failed you. That in itself is a good reason to fail you. If you can't tell that you haven't set the rivets properly than you need some more instruction. If a flush rivet isn't flush with the surface its not right. Smiley's aren't right. Even if your school didn't teach you these things one on one you are still required to know them for the test. The 43.13-1 and 2 have all that info and standards and there are other manuals or books out there with more. You can ask instructors for help or guidance as well. You are the one who needs to find the info you need to pass and the test guides will give you an idea of what can be asked or included in the tests. If you want to pass you need to make it happen.
I got my A&P through work experience and I worked on small aircraft (cessna, piper, beech etc) and built composite sailplanes yet I was still required to have all the knowledge of turbines and large aircraft to pass the tests. I had to spend some money on books and do some serious pre-internet research to pass the test. You can do it too just be the lead on the program instead of just a follower. Asking questions here is a great start so hit the books and let us know when you pass.

Frank
 
Let'sgoflying! said:
ah, ok - important info. Sometime early during the driving process you allowed the bucking bar to push the rivet out of the hole. No problem, you just have to push less on the bucking bar til the rivet swells enough to bind on the hole ID. Its a technique issue that I'm sure you will resolve with practice.
Push too hard on one end you get this, push too hard with the gun and you might deform the sheet.
Also be sure to have a bucking bar of adequate mass. You might be pushing too hard with it because it is too light.
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If I had 4 rivets to drive I'd not be breaking out a rivet gun or bucking bar. I have a 1 foot square 1 inch thick piece of steel that has a .401 hole in it to hold a rivet set.

Place the proper set in the hole, place a rivet in the set, add the 2 pieces of sheet over the rivet, smack once or twice with a ball peen and you are done.
 
To put this thread in prospective the test he was given is about a 4 or 5 minute test on joining two pieces of sheet with 4 rivets, no lay out, no pattern. That is the most simple rivet test I can think of. If he can't do that I'd fail him too.
 
smack once or twice with a ball peen and you are done.
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sounds practical, but do you really think he'd get a pass for demonstrating the correct way to rivet?
 
Tom-D said:
Riveting is easy, bend allowance is hard, try bending a "U" channel that will lie correctly in another "U" channel, and make the top edges the same hight.
Click to expand...

Do the attached drawings help?

Jim
 

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ajstoner21 said:
Well, I'm going as a night time student. it is about 3 years as night student, or about 2 years as a day student.
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Yeah, I did airframe/general in two years of high school and powerplant as a one smester add on after.
 
For some odd reason I want my A&P. But I just don't see when I'll be able to fit obtaining that goal into my life. So for now I wait.
 
Let'sgoflying! said:
sounds practical, but do you really think he'd get a pass for demonstrating the correct way to rivet?
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Yes.. It's how they look, not how it was done..

Every old Sheet metal working bench had a place to do that method of riveting. along with holes to except the various horns for working sheet stock.

for 4 rivets, I'd have asked for a rivet squeezer :)
 
weirdjim said:
Do the attached drawings help?

Jim
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All the drawings and formulas won't get the practical application done, I don't believe there are 5 A&Ps in the US that can walk up to the sheet metal break and get it right the first try.

when the formulas bring it out to .XXX" of set back, you can't read that on the brake. Its practical eyeball work, and unless you do it every day you'll miss it the first few tries.
 
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