INTERNATIONAL THREAD SERIES DESIGNATIONS

 

 

PARALLEL THREADS

M
ISO metric coarse thread
MF
ISO metric fine-pitch series
UNC
unified national coarse
UNF
unified national fine pitch series
UNEF
unified national extra-fine pitch series
UN
unified national 4-6-8-12-16-20-28 pitch series
UNS
special thread of america national form
UNJ Unified inch screw thread, constant-pitch series, with rounded root of radius 0.15011P to 0.18042P
UNJC Unified inch screw thread, coarse-pitch series, with rounded root of radius 0.15011P to 0.18042P
UNJEF Unified inch screw thread, extra-fine pitch series, with rounded root of radius 0.15011P to 0.18042P
UNJF Unified inch screw thread, fine-pitch series, with rounded root of radius 0.15011P to 0.18042P

 

 

PARALLEL THREADS  - GAS CYLINDERS
NGO
National gas outlet threads
NGS
National gas straight threads
NPS
National standard straight pipe
NPSC
American standard straight pipe thread in pipe coupling
NPSF
National standard internal straight pipe dryseal
NPSH
American std. straight hose coupling threads for joining to American Std taper pipe threads
NPSI
Dryseal American Standard intermediate internal straight pipe threads
NPSL
American Standard straight pipe threads for loose-fitting mechanical joints with locknuts
NPSM
American Standard straight pipe threads for free-fitting mechanical joints for fixtures

 

 

TAPERED THREADS
NPT
 National pipe taper thread
NPTF
 National pipe thread tapered fine pitch - Dryseal
FPTF
 Dryseal fine taper pipe thread series
NPTR
 National Pipe Taper Railing
NPTC
 National Pipe Taper Chlorine gas
NPTG
 American std. taper pipe thread for discharge valves for gas cylinders (except chlorine)
PTF-SAE SHORT
 Short Dryseal SAE taper pipe threads
PTF-SPL SHORT
 Short Dryseal special taper pipe threads

PTF-SPL EXTRASHORT

 Extra-short Dryseal special taper pipe threads
ANPT
 Aeronautical National Pipe Taper threads
NGT
 National gas taper thread
SGT
 Speciall gas taper thread
API
 American Petroleum Institute pipe taper thread

 

 

LEAD SCREW AND BUTTRESS THREADS
ACME-C
Acme thread centralizing
ACME-G
Acme threads, general purpose
STUB-ACME ACME flattopped thread
N BUTT
American national buttress thread

 

 

BRITISH SCREW THREADS
BSW
British Standard Whitworth coarse
BSF
British Standard fine thread series
BSC British Standard Cycle
BSPT
British Standard Pipe Taper thread
G/BSP
British Standard Pipe gas thread
BA
British Association thread
R Pipe thread external taper (ISO 7)
Rc Pipe thread internal taper (ISO 7)
Rp Pipe thread external parallel (ISO 228)
CEI Cycle Engineers Institute thread

 

 

OTHERS
NH
American national thread for unions of flexible pipes and fire hoses

 

 
Some interesting links:

Thread forms:  http://www.perfor.hu/pdfcat/ard194.pdf

Information on Screw Threads:  http://www.boltscience.com/pages/screw1.htm

Thread serire designation:  http://www.discount-tools.com/techcontents/006-007.pdf

Specifications of International Thread Standards: http://www.conexmetals.com/thread/specifications.htm

International Thread Standards:   http://www.gewinde-normen.de/en/index.html

ASME Thread Series Designations:   http://www.hemcogages.com/ansi.htm

An interesting blog:  http://practicalmaintenance.spaces.live.com/blog/



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