American Connections NPTF (National Pipe Tapered Fuel)

This connection is still widely used in fluid power systems, even though it is not recommended by the National Fluid Power Association (NFPA) for use in hydraulic applications. The thread is tapered and the seal takes place by deformation of the threads

Nominal Inch Dash Thread MaleThread FemaleThread Size Size Size O.D. Inch I.D. Inch Fraction Decimal Fraction Decimal 1/8 02 1/8-27 13/32 0.41 3/8 0.38 1/4 04 1/4-18 17/32 0.54 1/2 0.49 3/8 06 3/8-18 11/16 0.68 5/8 0.63 1/2 08 1/2-14 27/32 0.84 25/32 0.77 3/4 12 3/4-14 1-1/16 1.05 1 0.98 1 16 1-11-1/2 1-5/16 1.32 1-1/4 1.24 1-1/4 20 1-1/4-11-1/2 1-21/32 1.66 1-19/32 0.58 1-1/2 24 1-1/2-11-1/2 1-29/32 1.90 1-13/16 1.82 2 32 2-11-1/2 2-3/8 2.38 2-5/16 2.30

NPSM (National Pipe Straight Mechanical)

This connection is sometimes used in fluid power systems. The female half has a straight thread and an inverted 30° seat. The male half of the connection has a straight thread and a 30° internal chamfer. The seal takes place by compression of the 30° seat on the chamfer. The threads hold the connection mechanically. Note: A properly chamfered NPTF male will also seal with the NPSM female