Grease Fitting Symbols

N.P.T.

American Standard Taper Pipe Thread.

N.P.T.F.

Dryseal American Standard Taper Pipe Thread.

P.T.F.

Same as N.P.T.F. except full thread length has been shortened by one thread on small end of thread-also designated as P.T.F-SAE Short.

P.T.F Special Short

Same as N.P.T.F Short except one full thread has been shortened from large end of thread.

P.T.F Special Extra Short

Same as P.T.F Short except two full threads have been shortened from large end of thread.

N.P.S.F.

Dryseal American Fuel Internal Straight Pipe Thread.

N.P.S.I.

Dryseal American Intermediate Internal Straight Pipe Thread.

N.P.S.M.

American Standard Straight Mechanical Pipe Thread.

1/4"-28 Taper Thread (SAE-LT)

Thread has a 3/4" taper per foot and a pitch diameter of .2257 / .2224 at small end. The mating tapped hole is 1/4"-28U.N.F. 3B straight thread. Tap drill must not exceed .215" diameter.

1/4"-28 Special
Taper Drive Thread

Thread Forming-Forms thread in mating part during installation-when removed can be replaced by standard 1/4"-28 taper thread (SAE-LT) fitting.

1/8" Pipe Special
Taper Drive Thread

Thread Forming-Forms thread in mating part during installation-when removed can be replaced by standard 1/8"-27 P.T.F series fitting.

Straight

Mechanical

Intermediate

Lubrication Thread