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Motor, Nov 2007 by Mavrigian, Mike
Depending on the size of the AN hose end, assemblies with pipe thread connections are available in a full range of NPT (National Pipe Thread) sizes, from 1/8 in. all the way up to ½ in. (with ¾ in. also available from some makers).
Hoses
We've all seen braided stainless-steel hose with blue and red hose ends on custom cars and race cars. However, great strides have been made by the various hose makers, resulting in a wide array of choices with various benefits. There's certainly nothing wrong with stainless braided hose; it works great and looks great. The only downside is its weight and abrasive outer surface, which can scratch or even file through an adjacent surface if the hose rubs against it. Where weight savings are needed and/or abrasion damage needs to be avoided, the industry now offers a selection of hose designs that are lighter and won't abrade nearby surfaces, but will still provide the strong reinforcement and protection for the hose itself. One type isn't better than anodier; it's simply a matter of selecting the type that best suits a particular application or preference.
As an alternative to stainless braided hose, lighter-weight high-performance hose is offered with Kevlar outer woven braid or nylon braided sheathing, and special elastomeric hose that features no outer braided cover. Synthetic rubber hose featuring an interior braided fabric sheath (for strength) is available with maximum pressure ratings in the 250-psi range, and can be assembled using hose nipples and beaded tubing. Hoses with a tough, abrasion-resistant outer nylon sheathing bonded to a textile inner braid and synthetic rubber liner can be assembled using traditional AN hose ends or crimp hose ends, with maximum pressure ratings in the 1400-psi range. Ultra-light Kevlar-outer-sheathed hoses that are about 50% to 60% lighter than stainless-steel braided hoses, with maximum pressure ratings in the 1100- to 1200-psi range, also are available. But these may require the use of dedicated crimp hose ends. A wide range of choices are available today, not only in terms of weight, flexibility and materials, but in colors as well.
Fittings/Adapters
The fitting (also called the adapter) allows the connection of the nose end to the component. In some cases, the fitting will be provided as part of the component; for example, an engine oil cooler might already feature welded-on -10 fittings, so a -10 hose end will thread directly onto the cooler. In other cases, you'll need a separate fitting to finish the connection. Fittings are available with AN threads (and 37° flare seat) on one end, and an appropriate thread on the opposite end to fit the component. Let's say you need to plumb a -10 hose assembly to a water pump-to-heater routing and the pump has a ½-in. NPT female threaded hole. To complete the connection, you'll need an AN fitting that features a ½-in. male NPT thread at one end and a -10 male at the other to attach to the hose end. Fittings are available in a wide variety of both thread size combinations to accommodate any reasonably practical connection between various AN hose ends and NPT threads. Fittings are also available in straightthread (as opposed to tapered pipe thread), for locations that feature straight-thread holes. If the AN fitting features straight thread for the component connection, a sealing O-ring likely will be required.
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