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winkylocc

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I recently found myself on an interview for an Aircraft sheetmetal position that I had to fabricate some metal and shoot a number of solid rivets and install some anchor nuts. I did not have much experience with this while in the service and sure enough I failed. My question is what causes the rivet head to flatten when bucking? Should I invest in a pneumatic rivet squeezer and a number of different yokes until I get more experienced at using a gun and bucking bar? What is the purpose of the dimple die?
 
Check this out from Dan Checkoways' awesome site: http://www.rvproject.com/rivets.html

This should answer your first question.

You'll really want both a squeezer and a rivet gun. I have a 3x that I like and a tungsten bucking bar (plus others), a pneumatic squeezer with 3 yokes (a 3", a longeron, and a 4" no-hole), plus a manual squeezer (a "Main-Squeeze" from Cleaveland Tools). I try to squeeze as many rivets as I can, but there are simply many times when bucking is the only way so it's a skill you have to learn--it's not hard, just takes some practice.

The dimple dies (male and female) create a depression for the manufactured head of a flush rivet (ie. an AN426) to sit in after it's set so the the rivet head is flush with the surrounding material. Typically you'll dimple metal up to .040. Anything thicker you'll machine countersink to form the depression.

I'm about to rivet my tailcone. You're more than welcomce to come over and check it out. I live just North of Qantico Marine Corps Base off of I-95, about 30 miles South of downtown Washington.

Hope this helps!
 
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Auburntsts said:
Check this out from Dan Checkoways' awesome site: http://www.rvproject.com/rivets.html

This should answer your first question.
Click to expand...

Dan's explaination is close. The actual compression and deformation of the rivet occurs before the bucking bar moves in reaction to the blow of the rivet gun. Essentially the rivet is crushed between the rivet set of the gun and the bucking bar. It is the inertia of the stationary bucking bar that causes most of the hammering force to be absorbed by the rivet and results in the formation of the shop head. The energy not absorbed by the rivet is what causes the bucking bar to 'bounce'. In back-riveting the bucking bar (back-riveting plate) is confined such that more of the hammer force is contained by the rivet since the back-riveting plate cannot move.

As with most facets of building an airplane; practice, practice, practice. I can see differences between the quality of my rivets on the early parts and the parts I am building now. Made me think about building some of the tail kit pieces over, but only for a breif moment. I want to fly this thing someday (and they are really quite acceptable - I have an AP/IA to critique my work).

Dave
 
A pneumatic squeeze won't replace the gun and bar. Each of the three ways that I've used to "work" rivets has had its own uniques reason for that type of application.

I started out thinking that I would use the gun and bar for almost everything and a hand squeeze for everything else. Now, 3 hand squeezers, a pneumatic squeeze, several yokes and a gun with several bars later, I’m think I may still get one of those fancy tungsten bars.

There have been so many different situations requiring a different approach to riveting that there really isn’t any one good way to rivet. Skills are required for all – some more than others but you can’t take anything for granted. If you concentrate on one particular aspect of riveting and the next thing you know you have a rivet that sticks up a bit more proud and you really not sure why.

I've never heard of anyone using dimple dies in a rivet gun. I've used them in both the hand and pneumatic squeeze. Be careful with the pneumatic squeeze or you'll put a hole where there isn't supposed to be one, oops, I let that slip out.

Good luck
 
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