Conversion & Reference Tables
Thread Designations & Abbreviations
Conversion and reference tables to use alongside the thread charts.
- Sizes listed
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| Abbreviation | Country | Thread Angle ° | Description |
|---|---|---|---|
| ISO | – | 60° | International Organization for Standardization |
| UN | USA | 60° | Unified National 8-, 12- and 16 pitch series |
| UNC | USA | 60° | Unified National Coarse |
| UNEF | USA | 60° | Unified National Extra Fine |
| UNF | USA | 60° | Unified National Fine |
| UNJ | USA | 60° | Unified National thread series with external thread controlled root radius |
| UNJC | USA | 60° | Unified National Coarse thread series with external thread controlled root radius |
| UNJEF | USA | 60° | Unified National Extra Fine thread series with external thread controlled root radius |
| UNJF | USA | 60° | Unified National Fine thread series with external thread controlled root radius |
| UNJS | USA | 60° | Unified National Special thread series with external thread controlled root radius |
| UNR | USA | 60° | Unified National thread series with external thread controlled root radius |
| UNRC | USA | 60° | Unified National Coarse thread series with external thread controlled root radius |
| UNREF | USA | 60° | Unified National Extra Fine thread series with external thread controlled root radius |
| UNRF | USA | 60° | Unified National Fine thread series with external thread controlled root radius |
| UNRS | USA | 60° | Unified National Special thread series with external thread controlled root radius |
| UNS | USA | 60° | Unified National Special |
| NPT | USA | 60° | National Pipe Taper 1:16 |
| NPTF | USA | 60° | National Pipe Taper Fuel and Oil Dryseal 1:16 |
| NPTR | USA | 60° | National Pipe Taper Railing Fittings |
| NPSC | USA | 60° | National Pipe Straight Coupling |
| NPSF | USA | 60° | National Pipe Straight Fuel |
| NPSG | USA | 60° | National Pipe Straight Grease |
| NPSH | USA | 60° | National Pipe Straight Hose |
| NPSI | USA | 60° | National Pipe Straight Intermediate |
| NPSL | USA | 60° | National Pipe Straight Loose |
| NPSM | USA | 60° | National Pipe Straight Mechanical |
| BSW | GB | 55° | British Standard Withworth Coarse |
| BSF | GB | 55° | British Standard Fine |
| BSPP | GB | 55° | British Strandard Pipe Parallel |
| BSPT | GB | 55° | British Standard Pipe Taper |
| BA | GB | 47° | British Standard Association |
| NC | USA | 60° | National Coarse, replaced with UNC in 1948 |
| NF | USA | 60° | National Fine, replaced with UNF in 1948 |
Reference values only. Verify against the current edition of the governing standard before use in production drawings or manufacturing. Provided by Micro Components as a free engineering resource.