#12-24 UNC Thread Specifications
Complete dimensions for #12-24 UNC (Unified National Coarse) thread per ASME B1.1. TPI: 24, Pitch: 0.04167" (1.058 mm).
Thread Dimensions
| Designation | #12-24 UNC |
| Threads Per Inch (TPI) | 24 |
| Pitch | 0.04167" (1.058 mm) |
| Major Diameter | 0.216" (5.486 mm) |
| Pitch Diameter | 0.1889" (4.799 mm) |
| Minor Diameter (External) | 0.1649" (4.188 mm) |
| Minor Diameter (Internal) | 0.1709" (4.341 mm) |
| Thread Depth | 0.02255" (0.573 mm) |
| Tensile Stress Area | 0.02416 in² (15.6 mm²) |
Tap Drill Size
Recommended tap drill: 11/64" (0.1719" / 4.37 mm)
Calculated minor diameter (internal): 0.1709" (4.34 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 | 1,329 | 1,788 |
| Grade 5 | 85,000 | 120,000 | 2,054 | 2,899 |
| Grade 8 | 120,000 | 150,000 | 2,899 | 3,624 |
Same Size, Different Series
Common Applications
- Machine screws
- Electrical covers
- Small appliances
- Sheet metal