3/8-16 UNC Thread Specifications
Complete dimensions for 3/8-16 UNC (Unified National Coarse) thread per ASME B1.1. TPI: 16, Pitch: 0.0625" (1.587 mm).
Thread Dimensions
| Designation | 3/8-16 UNC |
| Threads Per Inch (TPI) | 16 |
| Pitch | 0.0625" (1.587 mm) |
| Major Diameter | 0.375" (9.525 mm) |
| Pitch Diameter | 0.3344" (8.494 mm) |
| Minor Diameter (External) | 0.2983" (7.577 mm) |
| Minor Diameter (Internal) | 0.3073" (7.807 mm) |
| Thread Depth | 0.03383" (0.859 mm) |
| Tensile Stress Area | 0.07749 in² (50.0 mm²) |
Tap Drill Size
Recommended tap drill: 5/16" (0.3125" / 7.94 mm)
Calculated minor diameter (internal): 0.3073" (7.81 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 | 4,262 | 5,734 |
| Grade 5 | 85,000 | 120,000 | 6,587 | 9,299 |
| Grade 8 | 120,000 | 150,000 | 9,299 | 11,624 |
Same Size, Different Series
Common Applications
- Structural brackets, automotive, equipment mounting
- Coarse thread applications