US Thread Chart

AMERICAN CONNECTIONS

National Pipe Tapered Fuel (NPTF) :

A connector with a dryseal thread, where the connection between the male and the female threads form a seal when the two threads are squeezed together (e.g. threads deformation). Teflon and pipe dope are typically used if this seal alone is not adequate. This connection is common in fluid piping systems - however, it is not recommended by the National Fluid Power Association (NFPA) for use hydraulic systems.

NOTE: The NPTF and BSPT connector are similar in appearance, however they are not interchangeable.

National Pipe Straight Mechanical (NPSM) :

A connection where the male thread (with a 300 internal chamfer), and female thread (with an inverted 300 seat), are both straight. When the two are threaded together, the tapered seat forms a leak-resistant connection. These connections are used widely across fluid power systems.

NOTE: A NPSM female and a chamfered NPTF male can form a seal together.

JIC 37° Flare (SAE J514) :

This connection is widely used in hydraulic systems, and both the male and female connectors have straight threads and a 37º flare seat. The straight threads of each half hold the connection together, sealing the flared seats.

NOTE: Most SAE J514 threads are exactly the same as the SAE 45º flare threads, however their seating angles differ.

SAE 45° Flare (SAE J512) :

Typically used with low pressure systems like refrigerant lines, fuel lines, and automotive applications, the SAE male and female connectors similarly have a 45° flare seat which forms the seal. The threads of both halves mesh together for a strong mechanical connection. The SAE 45° Flare connectors are exactly the same as the JIC 37° Flare connectors, however their seating angles differ.

SAE Straight Thread O-ring (O-Ring Boss) :

SAE J1926-1 and ISO 11296-1

A connection commonly found in high pressure hydraulic systems. While both halves have straight threads, the female has a sealing face and chamfer, and the male has an O-ring which when compressed into the opposing chamfer, forms the seal. The male and female threads mesh to form a solid connection.

Compression Tube Fittings (SAE J514) :

The female connector includes a compression sleeve, a female nut, and a tube. The male connector has a 240 seat, which makes the seal with the female compression sleeve (the seal forms on the female side between the tubing and the compression sleeve). With non-flared tube fittings with straight threads, the male and female threads mesh to form a solid connection.

O-Ring Face Seal (SAE J1453) :

These fittings join to form a highly leak resistive connection, in applications up to 6000 psi. Both halves have a straight thread, with the female having a flat surface and the male connector containing an O-ring. The seal is made when the O-ring on the male compresses against the flat surface of the female. The outside nut on the female connector holds the connection together.

SAE Inverted Flare (SAE J512) :

These connectors are widely used in the automotive industry. With the flared male tubing having a 450 seat, and the machined connector a 420 seat, the sealing surface is formed with the 420 seat on the end of the flare of the female connector. The male and female threads mesh to form a solid connection.

Four-Bolt Flange (SAE J518 and ISO 6162) :

These commonly used in fluid power systems, and suitable for joining 1/2" - 3" hose or tube. The seal forms between the flat surface of the female port and the O-ring of the male (seated in the ring groove). A split clamp, using 4 bolts, hold the male/female together.

Note that there are two types of SAE J518 flanges available: standard pressure (code 61), and high pressure (code 62).

O-Ring Pilot Threads :

These connections are typically seen in automotive and commercial air conditioning applications. Both halves of the connection have a pilot, making the seal by compressing the O-ring. The male and female threads mesh to form a solid connection.