[[TitleIndustry]]

An vs SAE vs NPT thread for different fittings

Date:Apr 11, 2020

The AN (Aerospace Standards) thread is a particular type of fitting used to connect flexible hoses and rigid metal tubing that carry fluid. It is are manufactured to MIL-F-5509 per AN (Air Force - Navy Aeronautical Standard) and AND (Air Force Navy Aeronautical Design Standard).. AN fittings are a flare fitting, using 37° flared tubing to form a metal-metal seal.

 

SAE thread is Industrial 37 degree flare fittings are manufactured to meet SAE J514/ISO-8434-2. Straight threads are per MIL-S-8879C now SAE-AS8879.. The differences between AN and SAE thread relate to thread class and shape (how tight a fit the threads are), and the metals used. As follow:

AN thread Fitting: 1/2-20 UNJF-3B

SAE Industrial fitting: 1/2-20 UNF-2B

 

NPT Pipe Threads: NPT pipe threads are your traditional tapered thread fittings and have been used for 100 years. They are available in low-pressure black iron and brass, and high-pressure steel and stainless steel. This connection style is used in pneumatic and process systems and hydraulic systems.

 

Note that 37° AN and 45° SAE fittings and tooling are not interchangeable due to the different flaring angles. Mixing them can cause leakage at the flare.

AN size

-2

-3

-4

-5

-6

-8

-10

-12

-16

-20

-24

-28

-32

Tube OD (inches)

1⁄8

3⁄16

1⁄4

5⁄16

3⁄8

1⁄2

5⁄8

3⁄4

1

1 1⁄4

1 1⁄2

1 3⁄4

2

Nominal hose ID (inches)

1⁄8

3⁄16

1⁄4

5⁄16

3⁄8

1⁄2

5⁄8

3⁄4

1

1 1⁄4

1 1⁄2

1 3⁄4

2

Actual hose ID (inches, approximate)

1⁄16

1⁄8

3⁄16

1⁄4

5⁄16

7⁄16

1⁄2

5⁄8

7⁄8

1 1⁄8

1 3⁄8

1 5⁄8

1 3⁄4

SAE thread size

5⁄16-24

3⁄8-24

7⁄16-20

1⁄2-20

9⁄16-18

3⁄4-16

7⁄8-14

1 1⁄16-12

1 5⁄16-12

1 5⁄8-12

1 7⁄8-12

2 1⁄4-12

2 1⁄2-12

Pipe thread size (NPT)


1⁄8-27

1⁄4-18


3⁄8-18

1⁄2-14


3⁄4-14







Previous: O-ring face seal vs o-ring boss seal fittings difference

Next: BA vs BSW vs BSF vs BSPC vs BSPP vs BSPT thread difference Fittings