Standard: BS 1768 - 1963
Available sizes: 1/4 to 7/16 (4 sizes)
| Size | P | e | r | k_max | k_min | s_max | s_min | ds_max | ds_min | k_nominal | ds_nominal |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/4 | 18 | 0.201 | 0.211 | 0.5000 | 0.4930 | 24 | 0.3125 | 0.483 | 0.473 | 0.3090 | 0.577 |
| 3/8 | 12 | 0.361 | 0.371 | 0.8125 | 0.8045 | 18 | 0.5625 | 0.792 |
Standard corrosion protection for indoor and mild outdoor environments.
Salt spray: 96–200 hours | RoHS compliant (trivalent chromium)
High-performance coating for automotive, marine, and harsh environments.
Salt spray: 720–1500 hours | Recommended for grade 8.8+
Heavy-duty protection for structural and outdoor applications.
Salt spray: 500–1000 hours | Thread tolerance adjustment required
Note for high-strength fasteners (Grade 10.9, 12.9): Electroplating processes require hydrogen embrittlement relief baking (minimum 4 hours at 200°C within 4 hours of plating). Contact our engineering team for grade-specific plating recommendations.
Request detailed technical specifications, material certifications, and availability information for your application requirements. Our engineering team can provide product recommendations, custom specifications, and technical documentation.
| 0.782 |
| 0.5585 |
| 0.938 |
| 5/16 | 14 | 0.281 | 0.291 | 0.6250 | 0.6170 | 20 | 0.4375 | 0.605 | 0.595 | 0.4335 | 0.722 |
| 7/16 | 10 | 0.463 | 0.483 | 1.1250 | 1.1150 | 16 | 0.7500 | 1.100 | 1.090 | 0.7440 | 1.300 |
© 2026 Ningbo Ruixi Metal Surface Technology Co., Ltd.. All rights reserved.