1-12 UNF Thread Specifications
Complete dimensions for 1-12 UNF (Unified National Fine) thread per ASME B1.1. TPI: 12, Pitch: 0.08333" (2.117 mm).
Thread Dimensions
| Designation | 1-12 UNF |
| Threads Per Inch (TPI) | 12 |
| Pitch | 0.08333" (2.117 mm) |
| Major Diameter | 1" (25.4 mm) |
| Pitch Diameter | 0.9459" (24.025 mm) |
| Minor Diameter (External) | 0.8978" (22.803 mm) |
| Minor Diameter (Internal) | 0.9098" (23.109 mm) |
| Thread Depth | 0.04511" (1.146 mm) |
| Tensile Stress Area | 0.66304 in² (427.8 mm²) |
Tap Drill Size
Recommended tap drill: 59/64" (0.9219" / 23.42 mm)
Calculated minor diameter (internal): 0.9098" (23.11 mm)
Proof Loads by SAE Grade
| Grade | Proof Stress (psi) | Tensile Strength (psi) | Proof Load (lbf) | Tensile Load (lbf) |
|---|---|---|---|---|
| Grade 2 | 33,000 | 60,000 | 21,880 | 39,782 |
| Grade 5 | 85,000 | 120,000 | 56,359 | 79,565 |
| Grade 8 | 120,000 | 150,000 | 79,565 | 99,456 |
Same Size, Different Series
Common Applications
- Heavy structural, foundation bolts, large machinery
- Fine thread applications