1-1/16-18 UNEF Thread Specifications
Complete dimensions for 1-1/16-18 UNEF (Unified National Extra Fine) thread per ASME B1.1. TPI: 18, Pitch: 0.05556" (1.411 mm).
Thread Dimensions
| Designation | 1-1/16-18 UNEF |
| Threads Per Inch (TPI) | 18 |
| Pitch | 0.05556" (1.411 mm) |
| Major Diameter | 1.0625" (26.987 mm) |
| Pitch Diameter | 1.0264" (26.071 mm) |
| Minor Diameter (External) | 0.9943" (25.256 mm) |
| Minor Diameter (Internal) | 1.0024" (25.46 mm) |
| Thread Depth | 0.03007" (0.764 mm) |
| Tensile Stress Area | 0.79861 in² (515.2 mm²) |
Tap Drill Size
Recommended tap drill: 1-1/64" (1.0156" / 25.8 mm)
Calculated minor diameter (internal): 1.0024" (25.46 mm)
Proof Loads by SAE Grade
| Grade | Proof Stress (psi) | Tensile Strength (psi) | Proof Load (lbf) | Tensile Load (lbf) |
|---|---|---|---|---|
| Grade 2 | 33,000 | 60,000 | 26,354 | 47,916 |
| Grade 5 | 74,000 | 105,000 | 59,097 | 83,854 |
| Grade 8 | 120,000 | 150,000 | 95,833 | 119,791 |
Common Applications
- Precision assemblies
- Thin-wall tubing
- Aerospace fittings