Abbreviations   Please advise of any errors or missions. This is an amateur site, and as such please confirm all information.

 If you don't find the thread you are after here please let me know and I'll attempt to add to this site.

16 UN  16 UNR thread

ACME-G  Acme thread general purpose

AMO  American standard microscope objective thread

AF  - measurement of spanner across the flats

AN   (JIC ??) Army Navy  (US military) parallel threads for flared 37o connectors

ANPT  American aeronautical pipe thread tapered

BA   - British Association standard thread (47 1/2o)

BSB  British standard brass (26 tpi)

BSCy  also BSC British Standard Cycle (identical to Cycle engineers institute thread)

BSCon British standard conduit thread

BSGas  British standard gas thread

BSW  - British Standard Whitworth

BSF   British Standard Fine

BSPE  Dont know???

BSPP   British Standard Pipe Parallel

BSPT   British standard taper pipe

BSP W   Dont know???

GHT Garden Hose Thread

in - inch

LHT   Left hand thread turn bolt or nut anticlockwise to tighten - (sometimes used on flammable gas threads and wheel studs on left hand side of some motor vehicles and left hand pedal of some push bikes.)

METRIC THREADS  it is not generally realised that several metric thread systems existed at one time. Owners of early continental machines may find screws that do not correspond with the ISO metric system)

M   ISO Metric screw thread coarse

????  Metric spark plug

ME  Model engineers thread

MF ISO metric fine pitch thread

mm   millimeter

N national 8, 12, 16 thread series (8N, 12N, 16N)

NButt   American buttress thread

NEF   National extra fine thread series

NC  - National Coarse (American)

NF - National Fine (American)

NGO  National gas outlet thread (specify left or right hand thread)

NPT  - National pipe taper thread (American)

NPTF National pipe taper thread (fuel and oil)

NPTR National pipe taper thread (railing joints)

NPS  National pipe straight thread

NPSC National pipe thread (pipe couplings)

NPSF National pipe straight thread (fuel and oil)

NPSH National pipe straight thread (hose couplings)

NPSI National pipe straight thread (intermediate)

NPSL National straight pipe thread (locknut)

NPSM National pipe straight thread (mechanical)

NPTF American National taper pipe thread for Dryseal pressure-tight joints

NS National thread (special)

NST Fire Hose Coupling 

P.T.F. SAE short taper pipe thread

PG Panzerrohr-Gewinde (steel conduit thread)

pitch  - distance between peaks of threads

RHT - right hand thread - turn bolt or nut clockwise to tighten.

SAE Society of Automotive Engineers

SB Stovebolt standard thread

SGT Special gas taper thread

????   Spark plug thread

STI Special thread for helical coil wire screw thread inserts

STUB Acme Stub acme thread

Selllers see William Sellers

 t - tapered

thou - one thousandth of an inch  .001"

tpi - Threads Per Inch

TR Trapezoidal thread

UN Unified national constant pitch thread series

UNC - Unified National Coarse

UNEF - Unified national extra-fine thread

UNF - Unified National Fine

UNJ   Unified national thread series with a 0.15011p to 0.18042p controlled root radius (external threads)

UNM Unified national miniature thread series

UNR Unified national constant pitch thread series with a 0.108p to 0.144p controlled root radius

UNS Unified national thread special

UTS   Unified Thread Standard

V a 60o "V" thread with truncated crest and root

W - Whitworth

WHIT Whitworth standard - special thread

Whitworth. - English inventor who described the whitworth thread system which has a thread angle of 55o and a round apex

William Sellers - American Inventor who described a thread with a 60o angle and a flat apex commonly used in many American threads

Please advise of any errors or missions. This is an amateur site, and as such please confirm all information