Technical Tips

• It is imperative that a clean, straight 90° cut be made on the hose end with a hose cutter designed for this purpose. A 90° hose end cut is the first step in insuring the proper installation of the hose fitting stem. If the hose end is cut on a "bias" or angle, the hose fitting stem barbs will not completely engage the hose inner tube. An assembly failure or fitting ejection is a possibility.
• A correctly cut hose end should always be cleaned, both inside and outside. Debris from the cutting process and other potential contaminants must be removed prior to assembly otherwise system components downstream may become clogged or fouled.
• Prior to assembly, a good practice is to align the fitting stem outside of the hose and place a mark on the hose indicating the end of the stem. Once the stem is inserted, this procedure provides a guide for the correct placement of a hose clamp. When using a ferrule and crimper, the crimper die engagement must be kept within the dimensional limits of the stem barbs as indicated by the mark on the hose cover. Failure to follow this guideline could result in the clamp forcing the fitting back out of the hose.

The SAE, in specification J530, is very specific as to the physical characteristics of pipe fittings in general as well as pipe threads. They detail such criteria as wall thickness, thread taper angles, major and minor diameters, profiles, etc. The SAE does not offer any stated or implied pressure ratings, however. There are three primary reasons for this apparent omission.

1. The multitude of different pipe thread types. Trying to rate NPT, PTF, NPTF and the British versions, BSP and BSPP, would be an impossibility especially since each size of each type would have to carry a separate rating.
2. Mating parts - A pipe fitting can be assembled into a machined part, forging, casting or molded part. It could be brass, steel, stainless, zinc, aluminum, plastic or other. Each has different thread sealing characteristics even though it is "pipe thread."
3. Assembly methods - There is no SAE specification relative to assembly torque or number of turns of engagement necessary to assemble. Here again, the number of variables are enormous and also dependent on the strength and determination of the assembler as well as the presence of a variety of thread sealing compounds.

A pipe fitting, and its connection, has only one mission and that is to not leak. Consider sealing all threaded connections including the Dryseal type.