AN Fittings

A Step By Step Guide for Assembling AN Fittings and Hoses

AN fittings and hoses are usually installed in high-performance vehicles like racing cars and aviation equipment because of their sturdy quality. Army-Navy or AN was a standard specification for fluid connection fittings that was developed during World War II. Currently, they are used in connecting the pipes that transport oil, fuel, coolants and hydraulic fluids. There are various fitting connections seen in high geared vehicles, including crimp type, push-lock and reusable hoses with or without swivel. 

There are numerous ways to assemble fittings and hoses in the equipment. Although the simplest way to learn about assembling the fittings is by watching the process, after knowing the basics of AN fittings and hoses, it would now be easy to understand the procedure used for their assembly through a brief description. 

1)    Step One: Load Them onto a Bench Vise

 The first step is to prep the hose by wrapping it with masking tape over the area to ensure a clean cut. Then it is loaded onto the bench vice, ready to be cut. 

2) Step Two: Cut the Hose Cleanly

The hoses are usually cut using various tools like sharp chisels, hammers, electrical cable cutters, and cut off wheels. All of these procedures have their advantages and disadvantages. 

  • Sharp chisel

A sharp chisel ensures a nice clean cut in the hose, although it might take a few hits with the hammer to cut through. The masking tape ensures that there is no fraying or debris. However, there is a slight possibility of the inner hose lining getting crushed from the numerous hits of the hammer.  

  • Electrical cable cutters

The electrical cable cutters are designed with sharp teeth that can chomp through the hose and the fittings. The masking tape prevents the braid from fraying here as well. And as mentioned above, there is a chance for the force of the electrical cutter to crush the lining of the fittings and the hose. They might have to be readjusted with a drift or a screwdriver to get the round shape back. 

  • Cut off wheel

Cut off wheels are commonly used for cutting items made of abrasive metals like AN fittings and hoses. They are designed to cut any material in front of them deeply with their straight/flat profile. One issue with using cut off wheels is that it produces a lot of debris when it cuts into the hose. After the cutting, one must ensure to clean out the pieces of burnt material left behind by the process; otherwise, they might affect the engine. 

Depending on the equipment one uses to cut the hose, they would have to clean up any sharp or uneven ends using side cutters and reshape the hose using screwdrivers or drifts. After a thorough cleaning, the fitting socket must be clamped onto the bench vice by forcefully pushing the hose down and twisting it into the socket.

3) Screw the Socket into the Fitting and Tighten It  

The next step is to lubricate the threads and hand threading the socket onto the fitting. One must be careful not to break the threading format while tightening them initially. To tighten it thoroughly, one must use a standard AN wrench or an assembly tool and inspect it and repeat the process wherever necessary. 
It is highly recommended to follow the safety guidelines and procedures given by the authorities while assembling AN fittings and hoses to avoid any accidents or damage. 


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