EngiRef / Metric Bolt Specification
M4
M4 coarse-thread metric bolt: 0.7 mm pitch, 4 mm major diameter. Tensile stress area 8.78 mm² per ISO 898-1. Takes a 7 mm wrench. Free bolt specification table…
Specification
- Size
- M4
- Pitch (mm)
- 0.7
- Major diameter d (mm)
- 4
- Minor diameter d₃ (mm, external thread)
- 3.14
- Tensile stress area (mm²)
- 8.78
- Head height (mm)
- 2.8
- Head diameter (mm)
- 7
- Wrench size (mm)
- 7
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.