EngiRef / UNC Bolt Specification
#8-32
#8-32 coarse UNC bolt: 32 threads per inch, 4.17 mm major diameter. Tensile stress area 9.04 mm² per ASME B1.1. Takes a 8.73 mm wrench. Free imperial fastener…
Specification
- Size
- #8-32
- Threads per inch (TPI)
- 32
- Major diameter D (mm)
- 4.17
- Minor diameter D₁ (mm, internal thread)
- 3.15
- Tensile stress area (mm²)
- 9.04
- Wrench size (mm)
- 8.73
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.