EngiRef / UNC Bolt Specification
1/2-13
1/2-13 coarse UNC bolt: 13 threads per inch, 12.7 mm major diameter. Tensile stress area 91.5 mm² per ASME B1.1. Takes a 19.05 mm wrench. Free imperial…
Specification
- Size
- 1/2-13
- Threads per inch (TPI)
- 13
- Major diameter D (mm)
- 12.7
- Minor diameter D₁ (mm, internal thread)
- 10.59
- Tensile stress area (mm²)
- 91.5
- Wrench size (mm)
- 19.05
Tensile stress area follows ASME B1.1, At = 0.7854(D − 0.9743/n)² in², converted at 645.16 mm²/in². Verify against the current standard and the fastener manufacturer's data before safety-critical design.