STANDARD MARKS OR SYMBOLS ON TAPS
|
MARK
|
MEANING OF MARK
|
| NC | American National Coarse Thread Series |
| UNC | Unified and American Coarse Thread Series |
| NF | American National Fine Thread Series |
| UNF | Unified and American Fine Thread Series |
| NEF | American National Extra Fine Thread Series |
| UNEF | Unified and American Extra Fine Thread Series |
| N | American National 8, 12, 16 Thread Series (8n, 12N, 16N) |
| UN | Unified and American 12 and 16 Thread Series (12UN, 16UN) |
| NH | American (National) Hose Coupling and Fire Hose Coupling Threads |
| NM | National Miniature Screw Thread |
| NGO | American (National) Gas Outlet Thread |
| NS | American Special Thread (60o thread form) |
| NPT | American (National) Taper Pipe Thread |
| NPTF | Dryseal American (National) Taper Pipe Thread |
| PTF | Dryseal SAE Short Internal Taper Pipe Thread |
| ANPT | Military Aeronautical Pipe Thread Specification MIL-P-7105 |
| NPS | American (National) Straight Pipe Thread |
| NPSC | American (National) Straight Pipe Thread in Pipe Couplings |
| NPSF | Dryseal American (National) Fuel Internal Straight Pipe Thread |
| NPSH | American (Standard) Straight Pipe Thread for Hose Couplings and Nipples |
| NPSI | Dryseal American (National) Intermediate Internal Straight Pipe Threads |
| NPSL | American (National) Internal Straight Pipe Thread for Locknut Connections (loose fitting mechanical joints) |
| NPSM | American (National) Internal Straight Pipe Thread for Mechanical Joints (free fitting) |
| NPTR | American (National) Internal Taper Pipe Thread for Railing Joints (mechanical joints) |
| AMO | American Standard Microscope Objective Thread |
| ACME C | Acme Screw Thread -- Centralizing Type |
| ACME G | Acme Screw Thread -- General Purpose Type |
| STUB ACME | Stub Acme Threads |
| N. BUTT | National Buttress Screw Thread |
| TO BUY BY CHECK |