AN stands for??

[James Montebello]

> I thought AN stood for airforce/navy as this is who the adapters were
> originally designed for.  As far as I'm aware there are only
> 2 types of fittings. AN and SAE.  AN flare is 37 degrees and SAE is 45
> degrees so they aren't compatible.  As for thread sizes they may or may
> not be the same I don't know.  But you don't want to get the flare wrong
> as it defeats the whole purpose of the high quality fitting.

There are also metric (seen on many European cars), NPT (not usually seen
used by OEM vendors, but often seen on cheaper aftermarket parts), BSP
(British Standard Pipe, seen on old English cars).  The flare mentioned is
where the male and female ends both end in a cone shape, one fitting inside
the other.  This ensures a good pressure-proof seal without O-rings. In
addition to thread diameters, there's also thread pitch (distance from
peak-to-peak), and thread form (how the deep the thread is, the shape of
the thread, etc.).  There are many to choose from.  The AN standard came
about since every vendor had its own style of fitting, and it drove the
military crazy having to stock a thousand different kinds of fittings to
fix stuff.

This is not a simple subject.

The way to avoid your own kind of craziness when buying fittings is to
do one of two things:  a) only buy fittings from one supplier (say,
Earl's), b) only use barbed fittings and hose clamps, since the fit
isn't quite so critical.  Either one will work for the kinds of
pressures normally seen on cars (with the exception of brakes).
The former is prettier and neater, but more expensive unless the
fittings will be taken apart frequently.

james montebello