2-4.5 UNC Thread Specifications
Complete dimensions for 2-4.5 UNC (Unified National Coarse) thread per ASME B1.1. TPI: 4.5, Pitch: 0.22222" (5.644 mm).
Thread Dimensions
| Designation | 2-4.5 UNC |
| Threads Per Inch (TPI) | 4.5 |
| Pitch | 0.22222" (5.644 mm) |
| Major Diameter | 2" (50.8 mm) |
| Pitch Diameter | 1.8557" (47.134 mm) |
| Minor Diameter (External) | 1.7274" (43.875 mm) |
| Minor Diameter (Internal) | 1.7594" (44.69 mm) |
| Thread Depth | 0.12028" (3.055 mm) |
| Tensile Stress Area | 2.49823 in² (1611.8 mm²) |
Tap Drill Size
Recommended tap drill: 1-49/64" (1.7656" / 44.85 mm)
Calculated minor diameter (internal): 1.7594" (44.69 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 | 137,403 | 184,869 |
| Grade 5 | 85,000 | 120,000 | 212,350 | 299,788 |
| Grade 8 | 120,000 | 150,000 | 299,788 | 374,734 |
Common Applications
- Industrial and structural applications
- Coarse thread applications