S-91257A165 1/2"-13 x 11" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance under extreme loads, preventing fastener failure in critical applications.
• Superior corrosion resistance from the zinc yellow-chromate plating extends service life, even in harsh or outdoor industrial environments.
• High hardness rating (Rockwell C33) provides excellent wear resistance and durability, maintaining thread integrity through repeated use.
• Coarse UNC threading with a Class 2A fit allows for faster assembly and easier alignment, reducing installation time and labor costs.
• Partially threaded design offers concentrated clamping force where needed, ideal for securing materials without unnecessary thread engagement.
• External hex drive and hex head facilitate secure tool engagement and high torque application, minimizing stripping and ensuring tight fastening.
• Compliance with ASME B18.2.1 and SAE J429 guarantees consistent quality, dimensional accuracy, and interoperability with standardized components.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address the demanding requirements of heavy-duty industrial applications, such as construction machinery, structural steel connections, and high-stress equipment assembly. The combination of high-carbon steel material and zinc yellow-chromate plating provides a robust solution against corrosion and mechanical wear, reducing maintenance frequency and downtime. The UNC coarse thread and Class 2A thread fit ensure quick, reliable installation in coarse-grained materials, while the partial threading concentrates clamping force to prevent joint loosening under vibration. By meeting ASME B18.2.1 specifications, it delivers predictable performance and compatibility, making it a trusted choice for engineers and procurement specialists seeking durable, high-strength fastening solutions.

Specification Summary & Compliance

This screw adheres to precise dimensional standards, including a Class 2A thread fit for consistent engagement and UNC coarse threading (1/2"-13) for optimal performance in various materials. It is manufactured in compliance with ASME B18.2.1 and SAE J429 specifications, ensuring reliability and interchangeability. The product meets common industry regulations for material and finish quality, supporting use in regulated environments where standardized components are required.