Well actually AFAIK the manufacturer considers the Avdel Cherry Textron Avex
rivet (yes that's the name on my catalog) to be a non-structural rivet because
it is not designed to retain a solid mandrel throughout the rivet's grip range.
The Q rivet and certified aircraft rivets retain the mandrel stem so that the
mandrel increases the rivet shear strength. As an example the 1/4" avex is 75%
stronger if you shear it where the broken off mandrel stem is. In any event, as
Bob said, the term "non-structural rivet" is really meaningless for us builders
since we are using the rivet that the designer specified.
Anyway Textron claims 165# in shear and 230# in tension for the 1/8" 1691 series
avex rivet but I don't believe anyone designs to those numbers. MAM has also
published 165# in shear and 225# in tension. In addition there seems to be a
common belief that the 1661 series rivets( manufactured in the British factory)
have higher quality control. The numbers for the countersunk rivet are a little
less but some knowledgable users claim that they are in fact significantly
weaker in real applications due to the heads breaking off. For comparison the
rating for the structural Q rivet is 350# in shear and 325# in tension.
What makes the avex rivet so good for us is how it is designed to expand
radially and fill the hole. This may make it better than some of the so called
structural rivets for our application. Better to have tight avex rivets than
structural rivets that work loose because they fill the hole poorly. Drilled
holes are certainly not perfectly round. Even worse might be to indiscriminately
substitute stainless rivets that may fill the hole poorly and also have a
tendancy to galvanically corrode the aluminum!
Ken
Bob Patterson wrote:
Hi Scott !>
Don't sweat it !! Avex and Cherry both come from Textron,
they're just different lines !!! All specs are available. Like
Cherry, there are different 'models' within the Avex line - some
are meant for non-aircraft applications, and you can't generalize
with the term 'Avex' - or 'Cherry', any more than you can with
'General Motors' - a Cadillac isn't <quite> the same as a Firefly,
although they both roll down the road. ;-)
The Avex rivets used on the Rebel ARE structural rivets.
You have to beware substituting anything on an aircraft - as
Wayne says "Watch out for the 'Bigger Bandaid' problem" !!
You can strengthen one area, only to cause larger problems
elsewhere !
While some builders have used solid rivets in places,
generally there is NO gain in strength, as the skin will tear
before the rivet shears, in most cases.
.....bobp
-----------------------------orig.----------------------------------
At 06:04 PM 7/9/01 -0600, you wrote:
Does anybody have the specs on the Avex rivets? I understand all Murphy
aircraft were designed to be more than strong enough with the Avex. Just
curious, as all the catalogs that I have list them "non-structural" and
never give the shear strength like they do with the Cherry rivets. Has
anybody out there substituted Cherry rivets in some places?
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