EngiRef / Metric Bolt Specification
M3
M3 coarse-thread metric bolt: 0.5 mm pitch, 3 mm major diameter. Tensile stress area 5.03 mm² per ISO 898-1. Takes a 5.5 mm wrench. Free bolt specification…
Specification
- Size
- M3
- Pitch (mm)
- 0.5
- Major diameter d (mm)
- 3
- Minor diameter d₃ (mm, external thread)
- 2.39
- Tensile stress area (mm²)
- 5.03
- Head height (mm)
- 2
- Head diameter (mm)
- 5.5
- Wrench size (mm)
- 5.5
Tensile stress area follows ISO 898-1, At = (π/4)(d − 0.9382p)². Verify against the current standard and the fastener manufacturer's data before safety-critical design.