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How to Order AN fittings

It is very easy to get confused when ordering AN pipe fittings, so here is a guide to try and help you find the right part number. AN fittings can have 3 different types of end:- a flared end (for fitting to pipe) with UNF thread, tapered end, with NPT thread or push on hose end. Each is measured in a different way as described below.

Flared End

These should be ordered based on the OD of the tube you are using.

Size Code

Tube OD in Inches


















For those that are interested, the size code corresponds directly to the tube OD in sixteenths of an inch. For example -8 would be 8/16 inches which is of course 1/2 inches.

Tapered End

These have a tapered NPT thread and are commonly used to screw into gascolators, fuel valves, brake callipers etc. With NPT the size does not denote the diameter of the thread but the diameter of the bore. As an aid here are a few measurements across the threads:

1/8 inch NPT = 5/16 inch

1/4 inch NPT = 7/16 inch

3/8 inch NPT = 9/16 inch

For fittings with mixed end types, several sizes can have the same size NPT end - allowing you to fit different sizes of tube depending on your requirements. These size codes are not listed here but are shown against each fitting.

Push on Hose End

Push on hose fittings are measured in a similar way to flared ends except that the dash number corresponds to the ID of the hose. -2 = 1/8 inch ID, -3 = 3/16 inch ID, etc

Bulkhead Fittings

These have an extra threaded section allowing them to pass through and be attached to a bulkhead. They should be used with an AN924 nut.

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