What's an AN fitting?
OK, so you're ready to order fittings for that new fuel system you just got.
Now there's only one thing: What's a 6 or 8 AN fitting?
"AN" (Army Navy) Sizes were established by the aerospace industry. The
measurements represent the O.D. (outside diameter) of rigid metal tubes.
Basically, dash sizes are the numerators of fractions with a denominator of 16.
EXAMPLE:
6 is equal to 6/16 in. which is equal to 3/8 in.
8 is equal to 8/16 in. which is equal to 1/2 in.
In the examples above, a 6 AN fitting would work with a pipe that has a 3/8 in.
O.D. A 8 AN fitting would be used with 1/2 in. O.D. pipe.
Here's a simple chart, just in case you don't want to do the math.
* 02 AN is equal to 1/8 in.
* 03 AN is equal to 3/16 in.
* 04 AN is equal to 1/4 in.
* 05 AN is equal to 5/16 in.
* 06 AN is equal to 3/8 in.
* 08 AN is equal to 1/2 in.
* 10 AN is equal to 5/8 in.
* 12 AN is equal to 3/4 in.
* 14 AN is equal to 7/8 in.
* 16 AN is equal to 1 in.
* 20 AN is equal to 1 1/4 in.
* 24 AN is equal to 1 1/2 in.
* 32 AN is equal to 2 in.
The most commonly used fittings are adapters. These adapters connect an AN
fitting to a pipe thread fitting. Most fuel pumps, regulators, and canister type
fuel filters, come with pipe thread inlet/outlet ports. In order to use braided
line, the ports need to be changed to a AN type of fitting. This is when a "pipe
to AN adapter" is needed.
The most popular sizes used in fuel systems are the 6 and the 8 AN,
although some high performance fuel pumps and regulators require a 10 AN
fitting.
