S-91257A750 1/2"-20 x 2 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum Load Capacity: Grade 8 classification with 150,000 psi tensile strength ensures reliable performance under extreme stress, preventing fastener failure in critical applications.
• Superior Corrosion Protection: Zinc yellow-chromate plating creates a durable barrier against rust and environmental degradation, extending service life in harsh industrial conditions.
• Precision Thread Engagement: Class 2A UNF fine threads provide excellent vibration resistance and secure fastening in high-performance assemblies.
• Optimized Torque Transmission: External hex drive with 3/4" head width delivers superior wrench grip and efficient installation with standard tools.
• Enhanced Design Flexibility: Partial threading allows for both clamping and alignment functions, ideal for components requiring precise positioning.
• Industry Compliance Assurance: Meets ASME B18.2.1 and SAE J429 specifications, guaranteeing dimensional accuracy and performance consistency.
• Environmental Responsibility: RoHS 3 and REACH compliance ensures safe usage while meeting global regulatory standards.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, this Grade 8 hex head screw combines high-strength steel construction with zinc yellow-chromate plating to solve critical fastening challenges. The 1/2"-20 UNF fine thread configuration maintains clamping force in vibrating environments, while the partial threading design provides unthreaded shank sections for precise component alignment. Ideal for heavy machinery, structural assemblies, and automotive systems, this fastener's Rockwell C33 hardness and 150,000 psi tensile strength prevent stripping and deformation under extreme loads. The external hex drive ensures reliable torque application during installation, making it suitable for both maintenance and manufacturing operations where durability and corrosion resistance are paramount.

Specification Summary & Compliance

This 2 1/2" length hex head screw features precise Class 2A thread fit with UNF thread standards and 1 1/4" minimum thread length. Manufactured to ASME B18.2.1 specifications and SAE J429 Grade 8 requirements, ensuring dimensional accuracy and mechanical performance. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, providing assurance for global supply chain integration.