Hydraulic fittings are one of the most important - and most overlooked - aspects of a hydraulic system. These humble components ensure a leak-free connection anywhere a hose connects to another component of the hydraulic system. They also allow components to be detached in order to conduct repairs or replace worn-out parts.

A perfect hydraulic fitting has yet to be invented. Yet fittings have improved and evolved significantly since the early days of hydraulics. Today, a variety of different fittings exist. If you would like to learn more about what sets these fittings apart from one another, read on. This article will provide a useful introduction to three of the most common types of hydraulic fittings.

JIC fittings fall into the broader category of flared hydraulic fittings. These fittings feature a tip whose diameter flares out to a 37˚ seating surface. For this reason, many manufacturers refer to JIC fittings as 37˚ flare fittings. A JIC fitting can only be used in conjunction with a tube or female fitting with a 37˚ flare.

JIC fittings create a seal through metal-to-metal contact. In other words, as the threaded outer portion of the fitting is tightened into place, the flared portion presses firmly against the end of the tube or hose. This method of creating a seal boasts much higher reliability than older systems, which featured unflared fittings and tubes.

A JIC fitting provides excellent results for sealing tubing with thin- or medium-thick walls. Thick tubing does not handle JIC fittings as well, owing to the difficulty of accurately flaring the tube. JIC fittings can handle operating pressures up to a maximum of 3,000 psi and are suitable for temperatures between 65 and 400 degrees Fahrenheit.

Flareless fittings, which historically have been used primarily in Europe, continue to gain popularity. As their name would imply, flareless fittings do away with the flares found on JIC fittings. Instead, the tip of the fitting has an acorn-like shape. This shape allows it to settle easily into the end of the tube, which features a 24˚ internal cone.

Flareless fittings offer exceptional sealing results. They also stand up much better to repeated usage, which means that the fitting can be loosened and tightened without serious structural ramifications. JIC fittings often suffer from metal fatigue as time goes on, which means that the flare may become misshapen due to over-torquing. This can make it harder to achieve a leak-proof seal.

Flareless fittings also make the process of sealing much easier. The acorn-shaped tip of the fitting will naturally shift into a tight alignment with the tube end as the fitting is tightened. JIC fittings lack this self-aligning capability. Instead, the installer must be careful to seat the fitting precisely inside of the tube end before tightening, otherwise, the seal may not hold up to high-pressure situations.

O-Ring Face Seal fittings - or ORFS fittings, for short - take a much different approach to sealing a hydraulic connection. Here the fitting has straight threading. A special grove machined into the face of the fitting allows a rubber O-ring to sit between the fitting and the tube end. As a worker tightens the fitting, the O-ring compresses, leading to a leak-proof seal.

ORFS fittings have gained popularity due to their leak-proof nature, which excels that of most metal-tometal fittings. Overtightening a metal-to-metal fitting can cause distortions and flexing that allows hydraulic fluid to escape the system. The rubber O-rings used in ORFS fittings allow them to deliver results across a much broader torque range.

Getting the most from a hydraulic system means equipping it with the right type of fittings. For more information about what fitting style best suits the needs of your hydraulic equipment, contact the experts at KIMS International.