#8-32 UNC Thread Specifications
Complete dimensions for #8-32 UNC (Unified National Coarse) thread per ASME B1.1. TPI: 32, Pitch: 0.03125" (0.794 mm).
Thread Dimensions
| Designation | #8-32 UNC |
| Threads Per Inch (TPI) | 32 |
| Pitch | 0.03125" (0.794 mm) |
| Major Diameter | 0.164" (4.166 mm) |
| Pitch Diameter | 0.1437" (3.65 mm) |
| Minor Diameter (External) | 0.1257" (3.192 mm) |
| Minor Diameter (Internal) | 0.1302" (3.306 mm) |
| Thread Depth | 0.01691" (0.43 mm) |
| Tensile Stress Area | 0.01401 in² (9.0 mm²) |
Tap Drill Size
Recommended tap drill: #30 (0.1285" / 3.26 mm)
Calculated minor diameter (internal): 0.1302" (3.31 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 | 771 | 1,037 |
| Grade 5 | 85,000 | 120,000 | 1,191 | 1,681 |
| Grade 8 | 120,000 | 150,000 | 1,681 | 2,102 |
Same Size, Different Series
Common Applications
- Machine screws
- Electrical covers
- Small appliances
- Sheet metal