Parker Hannifn Corporation
Parker Brass Products Division
Otsego, Michigan
Catalog 3501E
General Technical
N7
N
Thread Designations and Standards for Threads
Used in Fluid Connectors
Abbreviation
Description
Applicable Std.
Straight Pipe
NPSC
American Standard Straight Pipe Threads in Pipe Couplings
ANSI B1.20.1
Couplings
FED-STD-H28/7
NPSF
Dryseal American Standard Fuel Internal Straight Pipe Threads (generally
SAEJ476
used in soft or ductile materials to mate with NPTF external taper threads)
ANSI B1.20.3
FED-STD-H28/8
NPSI
Dryseal American Intermediate Internal Straight Pipe Threads (for brittle or
SAE J476
hard materials; intended to mate with PTF-SAE short external taper threads)
ANSI B1.20.3
FED-STD-H28/8
NPSM
American Standard Straight Pipe Threads for Free-Fitting Mechanical Joints
ANSI B1.20.1
for Fixtures (these threads ft freely over NPTF threads. They are used in
FED-STD-H28/7
swivel nuts of 07 adapters)
Taper Pipe
ANPT
Aeronautical National Taper Pipe Threads (similar to NPT with various
MIL-P-7105
additional requirements in gaging)
NPT
American Standard Taper Pipe Threads for General Use
ANSI B1.20.1
FED-STD-H28/7
NPTF
Dryseal American Standard Taper Pipe Threads (used in all of our steel and
SAE J476
brass fttings)
ANSI B1.20.3
FED-STD-H28/8
PTF —
Dryseal SAE Short Taper Pipe Threads (mainly used in low pressure pneumatic
SAE J476
SAE Short
and fuel applications)
ANSI B1.20.3
FED-STD-H28/8
PTF —
Dryseal Special Short Taper Pipe Threads
ANSI B1.20.3
SPL Short
1)
PTF —
Dryseal Special Extra Short Taper Pipe Threads
ANSI B1.20.3
SPL Extra Short
1)
Unifed Threads
UN
Unifed Constant Pitch Threads (standard series: 4, 6, 8, 12, 16, 20, 28, 32)
ANSI B1.1
FED-STD-H28/2
UNC
Unifed Coarse Threads
ANSI B1.1
FED-STD-H28/2
UNEF
Unifed Extra Fine Threads
ANSI B1.1
FED-STD-H28/2
UNF
Unifed Fine Threads
ANSI B1.1
FED-STD-H28/2
UNS
Unifed Special Pitch Threads
ANSI B1.1
FED-STD-H28/3
UNJ
Unifed Controlled Root Radius Threads
ANSI B1.15
FED-STD-H28/4
Table A48 — Thread Designations and Standards for Threads Used in Fluid Connectors (continued on the next page)
1) Used in some pneumatic components where shortened thread depth is required because of lack of enough material
due to component size limitations.