- As the name implies, ORFS, or (O-ring Face Seal) fittings incorporate an O-ring at the face of the fitting. Made to SAE J1453 standard, ORFS connections are commonly manufactured in carbon, nickel plated carbon & Stainless steel and typically use Buna-N or Viton, 90 Durometer O-rings that seat into a groove in the face of the fitting. This is known as an elastomeric seal.

- The seal is created when the o-ring compresses between the o-ring face of the fitting and flat face of the mating ORFS fitting or the formed tube. When the connection is tightened the O-ring compresses against a flat face of mating fitting or tube.

- Joint Industry Council fittings, defined by SAE J514, are compression fittings machined with a 37 degree flare seating surface and parallel threads. They are commonly manufactured in nickel alloys, brass, carbon & stainless steel.

- JIC Fitting hydraulic connections are common in most fluid power systems. Both male and female components have 37° seats. The seal is made by establishing contact between the male flared and the female coned seat. This is considered a mechanical connection. There are three components that make a tubing assembly; fitting, flare nut and sleeve.

- SAE Straight Thread O-ring Boss fittings, incorporate a port connection as recommended by the National Fire Protection Association (N.F.P.A.) for leak prevention in medium and high pressure hydraulic systems. ORB connections are commonly manufactured in carbon, nickel plated carbon & stainless steel and typically use Buna-N or Viton, 90 Durometer O-rings. The male connection is a straight UNF thread with an O-ring. The female port has a straight thread and a machined surface to provide a smooth, flat, accurately located surface (minimum spotface), along with a chamfer where the O-ring seats. The seal is created when the O-ring is compressed into the chamfer when mating the male and female connection providing a leak-tight seal.

- British Standard Pipe (BSP) is one of the most common fitting styles used worldwide. BSP is used on some of the world’s most recognized machinery such as Case IH, JCB, New Holland, and John Deere. British Standard Pipe threads are available in two versions, British Standard Parallel Threads (BSPP) and British Standard Pipe Taper (BSPT).

- BSPP is very similar in appearance to American National Pipe Straight Mechanical (NPSM) fitting but the two are NOT interchangeable. While both NPSM and BSPP seal on the cone seat of the male / tapered nose of the female, the threads are different in most sizes.

- BSPT is also very similar in appearance to American National Pipe Taper (Fuel) (NPT(F)) adapters but just like the BSPP/NPSM fitting connection mentioned earlier, the BSPT/NPT(F) are NOT interchangeable due to subtle differences in size and thread form.

- Japanese Industrial Standard JIS 30° Flare uses the same thread size and form as the British Standard Pipe family of fittings. The JIS 30° Flare is very similar in appearance to the North American JIC 37° fitting (SAE J514) but is NOT interchangeable due to the difference in the sealing angle and the thread form and size. The JIS 30° fitting connection features a 30° chamfered seat angle on the leading end of the male fitting that fits snugly against the 30° angle machined into the bottom of the female fitting forming a metal-to-metal seal when tightened.

- Note: the thread sizes are often expressed as fractional dimensions preceeded by the letters “G” or “R”, where “G” represents a parallel thread and “R” represents a tapered thread. Example: BSPT 5/8-14 can be designated by R 5/8 and BSP 1/16-28 can be designated by G 1/16.

Similar to heavy DIN metric fittings, light DIN metric fittings are a class of hydraulic adapter fittings frequently used in a variety of applications. They differ from other fitting techniques because of particular traits that they possess.

Design and Resemblance: Light DIN metric fittings resemble SAE (American) and British fittings in terms of design. They have metric threads and employ particular sealing techniques.

DIN Tube Fittings: The DIN tube fittings are one of the more well-liked light DIN metric fittings series. When connecting a DIN male fitting to a DIN female fitting, the sealing is done on the inside of the male fitting, which is where these fittings have a 24° chamfered seat. The 24° seat is used to identify DIN fittings.

Identification System: To ensure compatibility and appropriate fitting selection, search for the DIN tube design with a 24° chamfered seat, verify the indicated duty level (LL, L, or S), and figure out the thread pitch when recognizing or measuring light DIN metric fittings.

DIN fittings use an identifying scheme that is common among manufacturers. The tube series and outer diameter (O.D.) size are combined in this approach to identify the fitting. For instance, a fitting with an 8mm size and the designation "light duty" would be marked with the letters "L08."

The DIN designations different duty ratings are used to categorize DIN fittings:

• - LL (Extra Light Duty): Fittings designed for applications with minimal stress and pressure requirements.
• - L (Light Duty): Fittings suitable for light-duty applications with moderate stress and pressure requirements.
• - S (Heavy Duty): Fittings designed for heavy-duty applications with high stress and pressure requirements.

Thread Pitch: The thread pitch, which is the distance between two threads, is used to identify metric threads on DIN fittings. As opposed to American SAE and British Standard threads, which measure in threads per inch, this is different. All Metric DIN fittings use one of three standard thread pitches: 1.0mm, 1.5mm, or 2.0mm.

- Metric hydraulic adapter fittings resemble British and SAE (American) fittings in many ways.

- One of the most popular Metric fitting styles is the ISO 9974. ISO 9974 fittings are commonly used in hydraulic port applications. ISO 9974 fittings resemble SAE O-ring boss fittings and British Standard Parallel Pipe (BSPP) ISO 1179 fittings, the difference being metric threads. ISO 9974 fittings use a captive or retained seal at the base of the threads that mates to a seat surface on the female fitting or ported surface on a hydraulic cylinder or valve.

- Metric port fittings ISO 6149 also are very similar to ISO 9974 port fittings except they use a non-retained O-ring same as the SAE O-ring Boss Fittings.

- Another popular Metric fitting series is the DIN tube fittings. DIN tube fittings have a 24° chamfered seat on the inside of the male fitting that identifies the fitting as DIN, that 24° seat is where the seal takes place when joining a DIN male to a DIN female fitting. DIN fittings employ an identification system used by most manufacturers, this system combines the tube O.D. size and the tube Series, for example, a fitting that is 8mm and heavy duty would be marked “S08”.

DIN designations:

LL = Extra Light Duty

L = Light Duty

S= Heavy Duty

- Metric threads are called out using the distance between two threads as the Thread Pitch, this is different than American SAE and British Standard threads that are designated by Threads per Inch.

There are three common thread pitches used on all Metric DIN fittings, 1.0mm, 1.5mm & 2.0mm pitches.