<< > > > Robin wrote:
 > > >
 > > > Hello Paul,
 > >
 > > >     I hope this doesn't immediately sound like a dumb question, but how
 > can you find out exactly what the particular specifications for any given
 > "AN" part is?  For instance:  Metallurgist typically say there is just
about
 > no difference between an American made grade 8 bolt and an AN bolt.  Well,
 > that's fine and dandy and we all can see that relationship pretty well when
 > you're talking about common fasteners, but what happens when you begin to
 > talk about other products?  How can you really make a sound comparison?
 > >
 > > >     Let's face it, we're building experimental airplanes and we do a
lot
 > of things that wouldn't make muster for what we consider "AN" standards.
 > Nothing points this out more than the fact most of us on this forum are
 > working with rotary conversions.  Having said that, we all are trying to
 > build the safest airplane at the lowest possible cost too, so how do we get
 > the truth about the real differences between properties of different
 > products?
 > >
 > > >     Collectively, we believe the rotary is superior to the Lycoming,
and
 > we can prove it a dozen different ways.  It's when we begin to get into the
 > auxiliary systems that we always get into trouble.  Perhaps it's the way
 > we're thinking Paul.  If we can find superior engines to Lycoming, then why
 > isn't it just as probable that we might find superior "other" parts for our
 > installations?  The trouble is we don't have a good way to realistically
 > compare most of them.  Methods and materials are changing so fast we really
 > need some credible way to compare apples and oranges so we know which one
to
 > put in the salad.  Some of the new stuff might actually turn out being
safer
 > than the old tried and true AN product, but I'd prefer to find out about it
 > on the ground rather than in the air.  Unfortunately, it's likely to be we
 > experimental guys who find out first, one way or the other.  --  What are
 > your thoughts on how to compare apples and oranges in an evolving
 > environment?
 > > >
 > > > Robin

 Ian & Irene Beadle wrote:
 >
 > A grade 8 bolt, the same as an ordinary AN bolt! I don't think so. A mild
 > steel bolt with rolled thread to close tolerance cad. plated maybe, but
high
 > tensile grade 8!
 > Ian . Western Australia.

Too long a mystery. Big libraries have the specs on disc. The SAE specs you
have to buy from SAE in Warrendale Pa. However there are many handbooks
(Marks) that have some as lists and the library has that also. It is not a
question of this bolt is good, or that bolt is bad. It is the idea that an
oganization that is around year in and year out is available to identify a
source of supply for high quality fasteners and fittings. Even at that, once
the fastener is out of its packaging and the LOGMARs sticker is gone, there
is no tracability. The sticker has the manufacturers CAGE,
(Commercial And Government Entity) Like 00624 for Aeroquip. The part number.
In the AN bolts you can positivly identify the sizes. the date of
manufacture. And the contract number. A single AN dash 4 bolt might well be
connected to 50 specifications. For materials, thread forms, finish, tensil,
bending, marking, etc. Most will be government, or federal specifications.

Also there may be additional private specifications. So now you have a pile
of expensive handbooks on you table and you want to know what? You need to
know if it is a shear application a tension
application or both. Now you need an engineer. Have one at the begining or
near the end, you're going to need an engineer.

The really great bolts (the ANs and MSs) are made only by approved
manufacturers.
These manufactures keep samples of lots manufactured. For the absolute most
important fasteners, buy them new from (known) sources in the exact size
specified.

I run on......Lynn E. Hanover

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org