About Hex Bolt
Hex bolts and hex cap screws drive with a wrench or socket. The large drive area resists rounding, making them the mainstream choice for structural and machine assembly. DIN 933 is fully threaded, DIN 931 partially.
Standards DIN 933 · DIN 931 · ISO 4017 · ISO 4014
- Zinc-plated steel
- Lowest cost with adequate strength.
- Plain / black oxide steel
- Where the part will be painted.
- 304 stainless
- Outdoor, wet and food service.
- 316 stainless
- Marine and chemical.
How to choose
- In shear joints use partially threaded bolts so the plain shank takes the load.
- Stainless is weaker than high-tensile steel — do not swap by size alone.
- Stainless on stainless can gall; use anti-seize and moderate speed.