Guide to Hydraulic Hose Fittings Key Terms

Understand the terminology for hydraulic fittings to find the right ones

By Yvette Pryce

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Getting the best hydraulic fittings for the job is of utmost importance to keep hydraulic systems functioning at their peak. With fittings that aren’t perfectly suited to the application, you may end up with leaks or broken hoses. Gaining an understanding of the basic terminology associated with hydraulic fittings, however, will help you distinguish among fittings like flare type, bite type and swivel fittings, and it will also help you understand the differences between metal and thermoplastic fittings. With this knowledge under your belt, you can locate the best fittings for your application.

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All-metal fittings

All-metal fittings are, as their name indicates, metal, and they work well for metal-to-metal contact. All-metal fittings rely on threading to maintain the seal, and they may seep somewhat when you use them in high-pressure situations.

I recommend: Read about all-metal fittings, including why they aren’t always the best option, at "Hydraulics & Pneumatics."

Thermoplastic fittings

While most companies make fittings from metals such as brass and stainless steel, thermoplastic fittings are available in a range of plastics, including acetal, nylon and poly propylene. Thermoplastic fittings are appropriate for most uses and can be more affordable than metal fittings.

I recommend: Hydraulic House offers a full range of thermoplastic fittings.

Reusable fitting

A reusable hydraulic fitting is one that you can remove from a hose to use again on another hose, without any damage to the fitting, as opposed to crimp-style fittings that permanently attach to the hose. Reusable fittings are just as sturdy when you reuse them as they were in their original application.

I recommend: Tooling U offers a definition of a push-lock reusable fitting. You can see an example of a reusable fitting at Tallon Hydraulics.

Flare fittings

You can use a flare fitting with flared tubes. To do so, you place a flare fitting over the flared end of a tube to provide a secure hold.

I recommend: Find out about a variety of flare fittings, as well as other types of fittings, at "Machine Design."

Swivel fittings

A swivel hydraulic hose fitting allows for rotation of the fitting at slow speeds. Generally, a swivel fitting rotates less than 360 degrees.

I recommend: Review the product details of a number of swivel fittings at Drill Spot.

Bite-type fittings

A bite-type hydraulic fitting works in high-pressure situations. It literally "bites" into the hose when you install it, gripping the hose with a sharp edge on its ferrule, or clamp.

I recommend: At Swagelok, you can see a diagram of installed bite-type fittings, as well as diagrams of other fittings.