1-7/16-18 UNEF Thread Specifications
Complete dimensions for 1-7/16-18 UNEF (Unified National Extra Fine) thread per ASME B1.1. TPI: 18, Pitch: 0.05556" (1.411 mm).
Thread Dimensions
| Designation | 1-7/16-18 UNEF |
| Threads Per Inch (TPI) | 18 |
| Pitch | 0.05556" (1.411 mm) |
| Major Diameter | 1.4375" (36.512 mm) |
| Pitch Diameter | 1.4014" (35.596 mm) |
| Minor Diameter (External) | 1.3693" (34.781 mm) |
| Minor Diameter (Internal) | 1.3774" (34.985 mm) |
| Thread Depth | 0.03007" (0.764 mm) |
| Tensile Stress Area | 1.50303 in² (969.7 mm²) |
Tap Drill Size
Recommended tap drill: 1-3/8" (1.375" / 34.92 mm)
Calculated minor diameter (internal): 1.3774" (34.98 mm)
Proof Loads by SAE Grade
| Grade | Proof Stress (psi) | Tensile Strength (psi) | Proof Load (lbf) | Tensile Load (lbf) |
|---|---|---|---|---|
| Grade 2 | 55,000 | 74,000 | 82,667 | 111,224 |
| Grade 5 | 85,000 | 120,000 | 127,758 | 180,364 |
| Grade 8 | 120,000 | 150,000 | 180,364 | 225,454 |
Common Applications
- Precision assemblies
- Thin-wall tubing
- Aerospace fittings