Thread calculator
Free inch and metric thread dimensions, fits, measuring wires and tap drills. No account required.
ExampleDefault specification
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UnifiedDefault example
SPECIFICATION
0.2500-20 UNC-2A
Internal 0.2500-20 UNC-2B
ininches
ASME B1.1-2003 · UN / UNR profilesRight-hand thread1 start
Nominal diameter0.25in
Pitch0.0500in
Lead0.0500in
Thread profileUN60.0°
Diameter limits
External and internal dimensions, in inches.
| Dimension | Thread | Minimum | Maximum | Mean | Tolerance | Allowance |
|---|---|---|---|---|---|---|
| EXT | 0.2408 | 0.2489 | 0.2448 | 0.0081 | 0.0011 | |
| Major diameter | INT | 0.2500 | 0.2621ref | — | — | — |
| EXT | 0.2127 | 0.2164 | 0.2146 | 0.0037 | — | |
| Pitch diameter | INT | 0.2175 | 0.2224 | 0.2199 | 0.0049 | — |
| EXT | 0.1802 | 0.1948 | 0.1875 | 0.0146 | — | |
| Minor diameter | INT | 0.196 | 0.207 | 0.202 | 0.0110 | — |
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Thread profile
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Standards & sources
ASME B1.1-2003 · UN / UNR profiles
- ASME B1.1-2003 (opens in a new tab)UN and UNR inch thread forms, dimensions and tolerances. Official edition preview.
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