Strength Grade
Bolt grade is shown by dot-separated numbers (8.8, 10.9, 12.9); higher means greater tensile & yield strength.
| Grade | Description | Typical Use |
|---|---|---|
| 4.8 gr | General | General assembly, furniture, light load |
| 5.8 gr | Medium | General machinery |
| 8.8 gr | Medium-high | General machinery, equipment |
| 10.9 gr | High | Structural, automotive, engineering |
| 12.9 gr | Very high | Heavy load, high stress |
| A2-70 (304) | Stainless 70 | Corrosion-resistant, general strength |
| A4-80 (316) | Stainless 80 | Corrosion-resistant, high strength |
Notes
- Match grades: nut grade should not be lower than bolt to avoid thread failure.
- Preload control: critical joints need specified torque.
- No mixing: don't swap grades/materials casually — affects safety.
Grade and torque advice available on request with your condition.