A Practical Guide for Fittings and Hoses

A Practical Guide for Fittings and Hoses
source: monarchsupply.com

AN fittings and hoses are often mounted on high-performance equipment, like race cars, due to their sturdy build and quality. AN stands for Army-Navy as their structural and functional specifications were standardized during World War II for flexible fluid connections. AN hoses are used in connecting hydraulic fluids, coolants, oil, and fuel. They were initially used in the aviation industry, and then they eventually moved to be used for the high performance of racing cars and streetcars.

The sealing surface of AN fittings has a 37-degree flare. Therefore, they cannot be used with different types of flare fittings. Compared to the traditional hose clamps and push-on nipples, these provide a more secure fitting and reliable sealing for hoses. These can also be used for leak-free bulk pass-throughs used outside fuel stations.


Types of Army-Navy Fittings 

High-performance vehicles use three types of AN fittings based on how the hose is connected. They come in either swivel or non-swivel, which makes them easy for installation. These include:


1) Push lock

Push-lock hose fittings come as a single unit with a barbed end, making them the easiest to assemble. They usually do not have the provision to prevent the braid from loosening, so push locks are used with coated hoses. The hose is hoisted and seated over the bard that can hold the hose in place, sometimes with an additional clamp.

2) Reusable hose ends

Reusable hose ends are made of two pieces or parts that clasp the hose in place. Generally, they are used with nylon braid or stainless-steel braided hoses varying in different sizes, colors, and angles. When compared to push locks, these fittings are slightly heavier and provide a steadier hose clamping method. They use this by untethering the hose end sockets from the main body and inserting the braided hose into the socket. The inner diameter of the hose tapers when the socket is strung over the nipple, and the clamps maintain this pressure to prevent leaks.

3) Crimp type

Crimp fittings are produced using a hydraulic press and special dyes to crimp the collar onto the ends of the hoses accurately. The dyes and the machines used are expensive, and hence they are usually produced in bulk, in various facilities, and not by individuals. If crimped correctly, these are considered to be the strongest and the most reliable amongst all three.


Tools and Equipment Used for Army-Navy Fittings

AN fittings can be marred using standard wrenches as they are generally made of aluminum. There are specific anodized aluminum wrenches available for use to prevent excess damage to the surface of the fittings. Some popular AN assembly tools include a cutter, a bench vice, a masking tape, pinch clamp pliers, work gear hose clamps, a nut driver, and AN wrench. Aluminum vice jaws are also used to hold the fittings in place and protect them from leaks.

Assembling AN fittings is one of those tasks that can be learned best by visual and kinesthetic involvement. The more one does it, the better they get. It is recommended to inspect the quality of the fittings and hoses during purchase and up to the completion of the fitting. Follow the safety guidelines provided by the experts and authorities to prevent causing any accidental damage.