It’s 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.
A fitting can have 1 of 4 different ends:
Flared end (for fitting to pipe), with UNF thread
Tapered end, with NPT thread
Push on hose end
These should be ordered based on the OD of the tube you are using. The table below shows which size fitting is suitable for which size tube.
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” which is of course 1/2”.
These have a tapered NPT thread and are commonly used to screw into gascolators, fuel valves, brake callipers etc. Remember that 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” NPT = 5/16”
1/4” NPT = 7/16”
3/8” NPT = 9/16”
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. For that reason size codes are not listed here but are shown against each fitting type.
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.
These have an extra threaded section allowing them to pass through and be attached to a bulkhead. Use with an AN924 nut.
