S-91257A819 5/8"-11 x 6 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum Load-Bearing Capacity: Grade 8 classification and 150,000 psi tensile strength ensure reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior Corrosion Protection: Zinc yellow-chromate plating provides excellent resistance to rust and environmental degradation, extending service life in harsh industrial conditions.
• Optimized Thread Engagement: UNC coarse threads and Class 2A thread fit enable faster assembly and better vibration resistance compared to fine-thread alternatives.
• Enhanced Torque Transmission: External hex drive design with 15/16" head width allows for high torque application using standard tools, minimizing stripping risks.
• Precision Engineering: Partially threaded shank design provides unthreaded bearing surface for improved clamping force distribution in structural connections.
• Industry Compliance: Meets ASME B18.2.1 and SAE J429 specifications, ensuring interchangeability and reliability across industrial applications.
• Environmental Responsibility: RoHS 3 and REACH compliance demonstrates commitment to regulatory standards and workplace safety.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver exceptional performance where high tensile strength and vibration resistance are critical. The steel construction with Rockwell C33 hardness provides the ideal balance between strength and ductility, preventing brittle failure under dynamic loads. The zinc yellow-chromate plating offers superior corrosion protection for outdoor equipment, machinery, and structural assemblies exposed to moisture and chemicals. With 5/8"-11 UNC coarse threads and Class 2A thread fit, these partially threaded fasteners ensure secure fastening in construction, manufacturing, and automotive applications where reliability cannot be compromised. The external hex drive design facilitates efficient installation in confined spaces using standard wrenching tools.

Specification Summary & Compliance

This 6 1/2" length hex head screw features 5/8"-11 UNC coarse threads with Class 2A thread fit precision and 1 3/4" minimum thread length. Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and mechanical properties. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making them suitable for global industrial applications requiring strict regulatory adherence.