AN stands for??

[James Montebello]

AN stands for Army/Navy.  It refers to a standard developed by the US
military 50-60 years ago.  The AN 'dash' number (AN-4, AN-6, AN-12)
refers officially to the OD of a tube, but in practice has come to 
refer also to a particular size of threaded fitting.  Larger numbers
mean bigger sizes.  -4 is typically used for fuel lines, -6 for brake
lines, -12 or -16 for oil lines.  The aerospace industry uses this
stuff all over the place, and because of the high-quality of the parts,
the racing crowd started to use it, too.

Fittings used by most auto manufacturers are either NPT (National
Pipe Thread) or metric, probably using some ISO standard for thread
pitch and form.  Adapters are readily available to convert AN to 
NPT and AN to metric.  If you want a source of AN fittings, look
around for a distributor of Earl's or AeroQuip.  Most decent hot-rod
shops will know about this stuff.  Really good ones will stock it.

james montebello


> -----Original Message-----
> From: owner-diy_efi at efi332.eng.ohio-state.edu
> [mailto:owner-diy_efi at efi332.eng.ohio-state.edu]On Behalf Of Clarence
> Wood
> Sent: Friday, March 19, 1999 2:39 PM
> To: diy_efi at efi332.eng.ohio-state.edu
> Subject: AN stands for??
> 
> 
>   I am at a loss.  I can not find out what an 'AN' size 
> fitting is/means.  I have found out that 'Boss' is the same 
> thread size.  I can go into a parts store and ask for a #10 
> MB (Male Boss) fitting and it is exactly the same as an AN 
> #10 fitting; the only difference is that the guys in the 
> parts store don't know what an AN is.  When I took my FPR in 
> and showed them they said "Ah hell, that's a #10 MB to 3/8 
> fitting".  Can anybody tell me what the history of 'AN' is?  
> Also, what is the history of Boss, and why are they the same 
> but called different names?
> 
> Clarence
> 
> 
> IZCC #3426
>  1982 280ZX Turbo GL
>  1966 El Camino
>  1982 Yamaha Maxim XJ-1101J Motorcycle
>  1975 Honda CB750 SS (black engine)
>  1986 Snapper Comet lawn mower
> Clarence Wood
> Software&Such...
> clarencewood at centuryinter.net
> Savannah, TN.
>