#2-56 UNC Thread Specifications
Complete dimensions for #2-56 UNC (Unified National Coarse) thread per ASME B1.1. TPI: 56, Pitch: 0.01786" (0.454 mm).
Thread Dimensions
| Designation | #2-56 UNC |
| Threads Per Inch (TPI) | 56 |
| Pitch | 0.01786" (0.454 mm) |
| Major Diameter | 0.086" (2.184 mm) |
| Pitch Diameter | 0.0744" (1.89 mm) |
| Minor Diameter (External) | 0.0641" (1.628 mm) |
| Minor Diameter (Internal) | 0.0667" (1.693 mm) |
| Thread Depth | 0.00967" (0.246 mm) |
| Tensile Stress Area | 0.00370 in² (2.4 mm²) |
Tap Drill Size
Recommended tap drill: #51 (0.067" / 1.7 mm)
Calculated minor diameter (internal): 0.0667" (1.69 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 | 204 | 274 |
| Grade 5 | 85,000 | 120,000 | 314 | 444 |
| Grade 8 | 120,000 | 150,000 | 444 | 555 |
Same Size, Different Series
Common Applications
- Machine screws
- Electrical covers
- Small appliances
- Sheet metal