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CH701 AVEX rivets

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wwalton

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Hello fellow tin men. I was just looking at the assembly instructions for my 701 rudder starter kit and discovered that ZENITH calls for a special head for the rivet puller and that the rivets are countersinks and the special head shapes them into domed heads, I guess I had missed this before. I have searched around the forum and their site and I can't find much about this. Is this a common practice or something that Mr. Heintz came up with? Should I use another kind of rivet Cherry N and just use the puller that I have? I love the plane and the construction method, I just feel this is a little funky? If you wanted domed rivets why not use them to begin with. Anyways just looking to see if anybody else had an issue with this, I'm new at this building thing.
Thanks
Walt
STOL 701 builder
 

Dave068

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Mar 20, 2005
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search the zenith site and I believe you will find that they will machine the riveter head for you. The cost is somewhere in the 5-10 dollar range.
 

Midniteoyl

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http://www.zenithair.com/kit-data/tools.htm

Riveter Heads (changeable Nose Bushing piece): Zenith Aircraft Company has developed a unique process for setting blind rivets, which requires custom rivet heads. The process uses flush-type rivets, where the flush rivet head is formed into a domed-head by the riveting process. This provides an permanent tight finish to all set rivets. To accomplish this, the riveter heads must be ground (machined) with a concave dome (see diagram). Only 1/8" (A4) and 5/32" (A5) rivets are required to assemble the kit
 

Midniteoyl

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They say its 'tighter'. Looking at it, I could see why, though I havent actually tested it. I do know that domed head rivets used with a flat rivet head usually results in a flattened rivet anyway, so maybe having a concaved head is not a bad idea no matter which one is used.
 

wwalton

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Well that was my question, why not just use a dome rivet? I am sure with all the Zenairs flying that this is safe. I just don't really like the idea of reshaping a rivet that was obviously not meant to be driven that way. With that said, I ordered their machined rivet heads for the a4 and a5 avex rivets. They are $12 each. If it wasn't for their track record and hundereds of planes flying I would not use this method. Thanks for all the help gentlemen.
 

Rhino

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I think their premise is that it's better waterproofing than a dome rivet.

Besides, aren't domed rivets driven rivets rather than pop rivets? If that's the case, then it answers your question. Popping is obviously easier than driving. And standard pop rivets are notorious for setting loosely sometimes. Besides being structurally less sound, that promotes moisture contamination. That was apparently the reasoning behind Zenith's redesign.
 
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wildun

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May 10, 2007
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The idea I think is to get a tight fit in the hole, the tapered part of the rivet head is forced into the hole and the rest of the ( tapered ) head is then curved down and pushed against the top of the skin, this effectively results in the rivet being wedged tightly in the hole as well as the head being pressed down on the top of the skin.
Whereas an ordinary domed rivet does not seal the top of the hole so effectively because the stem just under the head will not be such a tight fit in the hole.
 

gahan

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Dec 27, 2004
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three rivers mi..
we used to use huck and cherry lock rivets they both had a locking collar that was set just as the rivet was drawn to it's correct grip, these air guns were expensiveand somewhat compilcated, if youdidn't have it set up perfect the locking collar could come loose and potentialy let the center draw pin vibrate out , this leaves the rivet with little shear strength ,and a loose nail running around the inside of your aircraft,I think reforming the rivet head is more for getting a better bite in the pin , I THINK!
 

base363

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Nov 5, 2006
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I have the machined heads, and plan to use the Avex rivets on a wing project I’m working on.

I have pulled several, and the process seems to work as advertised!

The Avex rivets are also allot less expensive than the conventional Cherry rivets.

There are instructions available, on how to machine your own heads as well.

I think they are posted on a Yahoo Zenith builder’s group?

Colin

http://www.jumprunenterprises.com
 

Kgblue57

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Jul 25, 2007
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I took took my standard rivet head and ground it out with my dremmel tool. It forms a great domed head on the rivet.
 
M

MartyD4u

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Lock-down on Rivets?
Only 1/8" (A4) and 5/32" (A5) rivets are required to assemble the kit
The Zenith 701 rivets can only be bought from zenith at .08 cents each? (imported from England). I looked for other AVEX suppliers but can't seem to find A4 or A5 in the suppliers catalog? Plus I would need testing documents with them... any idea where I can purchase this documented rivet? Scratch building Zenith 701 in Hammond, Louisiana trtying to save a penny or two. 6 thousand rivets add up quickly.
Marty
 

Mapleflag

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Jun 27, 2010
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Ontario, Canada
I am new to this forum and have found it very useful while researching the various make and models of homebuilt aircraft available. I have an aviation background, initially as an AME and now after the lobotomy as a commercial pilot. I found it was a lot more fun to break them then fix them!!! I have settled on the Zenith CH650B (I am Canadian after all). With the hope of envolving my children the simple construction techniques required where a leading factor. The use of AVEX/Cherry Max style rivets certainly is central to the simplicity I was seeking.

I have a concern based on the diagram that outlines the rivet setting process. A counter-sunk rivet is specified but if the hole is not perfectly drilled or properly de-burred rivet material could be forced downward in to the hole. To my way of thinking this creates the possibility of stress cracking occuring over time in the radius of the hole and then being hidden from view under the formed/forced braizer head. The best option I see to limit the risk is a return to a pneumatically driven brazier head, dimple or counter-sunk rivet. This however removes one of the biggest attraction of the construction process.

I was hoping to introduce my children to aviation in the airplane they helped to build and then to go on to fly it themselves, there is enough risk in that already!!! Am I being overly concern.


 

Taiser

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Nov 28, 2010
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Lock-down on Rivets?
Only 1/8" (A4) and 5/32" (A5) rivets are required to assemble the kit
The Zenith 701 rivets can only be bought from zenith at .08 cents each? (imported from England). I looked for other AVEX suppliers but can't seem to find A4 or A5 in the suppliers catalog? Plus I would need testing documents with them... any idea where I can purchase this documented rivet? Scratch building Zenith 701 in Hammond, Louisiana trtying to save a penny or two. 6 thousand rivets add up quickly.
Marty

Hmmm, Ex-AME here as well.

I'm scratch building a 750, (just ordered the plans, getting my shop ready) and did not know these rivets were so rare...somebody besides Zenair must sell these things?? I don't mind ordering from them, but I assumed my local fastener shop would be able to get these as well. How hard are they really to find??
 

thetford

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Feb 15, 2009
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Birmingham, Alabama
Avdel Global markets the "Avex" rivets... they are manufactured in China, and from personal experience the quality varies from batch to batch. The A4/A5 aren't hard to find. You can always ask Chris what his tension/sheer spec is on a given rivet area/application and use this info to cross reference cherry or others if you don't want to use the Avex.
 

Taiser

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Nov 28, 2010
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Location
Ontario Canada
Avdel Global markets the "Avex" rivets... they are manufactured in China, and from personal experience the quality varies from batch to batch. The A4/A5 aren't hard to find. You can always ask Chris what his tension/sheer spec is on a given rivet area/application and use this info to cross reference cherry or others if you don't want to use the Avex.

Thanks, but I've already ordered the hand and pneumatic rivet gun from Zenith so I prefer to use the rivet called for. Hopefully I can find a local dealer, even if he has to order them in. :)
 
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