The Murphy Builders Site

This doesn't add anything to the knowledge base of Avex style rivets but since
we're talking about funky rivets......... I recently did a tensile failure test
on a more or less garden variety 1/8" x 3/8" aluminum dome head POP in
polyethelyne and managed to fail the rivet by pulling the flange off at a load
of about 380 lbf.

If our Avex are better than garden variety POP then the stated ultimate strength
may be including a generous factor of safety. The only thing that
differentiated these rivets from hardware store units was they had
circumferential grooves around the body to grip the sides of the hole when
expanded.

Who'da thunk that you'd break the rivet before pulling it out of plastic!

Dave





"Wayne G. O'Shea" wrote:

Those where the only rivets Chris H could get for his first Zenith and it's
hard to teach an old dog new tricks ! LOL Just joshin...he just lives up the
road and a great fella.

----- Original Message -----
From: <bransom@dcsol.com>
To: <rebel-builders@dcsol.com>
Sent: Thursday, December 13, 2007 11:47 AM
Subject: Re: [rebel-builders] R4412 rivet strength, weather stripping

Ken
Thanks for the actual numbers. Good points.

off-topic....
I was surprised to learn that the rivet widely used on the Zenith is the
R4412, without countersinking the holes. They use a funkified (concave)
riveting head tool that causes the crown of the 4412 to knurl over. I
guess the thinking is that it increases tensile strength and maybe
slightly
lower profile still. I can't see messing with a rivet manufacturer's
design myself. ...also can't see messing with a Zenith ;)
-Ben

Well...
The Low Profile head is rated165 lb shear and 230 lb tension.
True the c.s. head is rated 155 lb shear and 205 lb tension.
The shear number is generally the important one for us so the c.s. is
94% the strength of the low profile dome head. There are some reports of
the c.s. heads separating prematurely but there are other claims that
the c.s. head adds shear strength.

Personally I would not give it a second thought. I believe the rivets
are fully interchangeable and both have more than adequate safety
factor. I'm pretty sure MAM has said the same thing but ask them if you
are concerned. With thin skins the rivets are not the weak link in most
cases. ie extra rivets are there to reduce tearout, not because that
much rivet strength is needed.

Ken

bransom@dcsol.com wrote:

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--
David A. Ricker
Fall River, Nova Scotia
Canada






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