David, with that all said, I guess I need to slow down my work
pace!!!!!! This is a good thing I guess, because I charge by the
hour!!! When you had Rivets Unlimited on the phone, did you complain
they make them oversize and your fingers are killing you from putting
them in the holes! Blues skies,Wayne
-----Original Message-----
From: David A. Ricker <
ricker@dbis.ns.ca>
To: Murphy Rebel Builders List <
murphy-rebel@dcsol.com>
Date: Wednesday, March 22, 2000 12:04 PM
Subject: Re: [Fwd: Rivets]
This is bad, I am not getting any work done!
OK, called AVDEL, they said you want a nice symetric bulb to
be formed when the rivet pulls but would not commit to how
far the mandrel should pull in to the barrel of the rivet.
Called Rivets Unlimited. They have the rivets we are
getting from Murphy made to their spec. They say that you
want a nice symetric bulb to be formed when the rivet pulls
and that dome of the mandrel should not pull very far into
the barrel of the rivet. I described what one of the
hand/low pressure pulls looked like and he said this was
what they were looking for. The head just pulls into the
barrel leaving the dome of the mandrel sticking out .030 -
.050" & is gripped at the edges.
He said that if it is pulled fast/hard enough that the
mandrel will pull down into the barrel until the added
resistance from the sheet you are riveting stops it from
stretching radially then the mandrel breaks. This will
leave the broken end of the mandrel protruding in thin
materials.
Both Avdel & RU stated that the mandrel was designed to
break at a set static loading. Adding in the dynamic action
caused by the speed at which the air riveter will pull at
high pressure you get into a hazy area where the loading of
dynamic friction is different from static and also things
under shock loading act differently than quasi-static. The
load on the mandrel doesn't reach break until the barrel is
deformed more than the design called for and the mandrel is
pulled farther into the rivet barrel. That said, I have
seen some variation in the shape of the set rivet even using
low pressure (and presumably would occur by hand also....)
so I am sure there is some variation in the material
properties from rivet to rivet.
Well folks, there you have it, this is what I have learned
this morning, I hope it is useful and it is presented with
that in mind. As with any of the information you see here,
you mileage may vary so satisfy youself that what you are
doing is correct and then proceed!
Back to work now...
Dave R.