S-91257A485 7/16"-20 x 7" 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, reducing the risk of fastener failure in critical applications.
• Superior corrosion resistance with zinc yellow-chromate plating protects against rust and environmental degradation, extending service life in harsh conditions.
• High hardness rating of Rockwell C33 provides excellent wear resistance and maintains thread integrity during repeated assembly and disassembly.
• Precision UNF fine threading with Class 2A fit offers secure, vibration-resistant connections and easier alignment in fine-pitch applications.
• Partially threaded design allows for controlled clamping force and prevents over-tightening, ideal for components requiring specific grip ranges.
• External hex drive and hex head facilitate quick installation and high-torque application using standard tools, improving assembly efficiency.
• Compliance with ASME B18.2.1 and SAE J429 standards guarantees consistent quality, dimensional accuracy, and interoperability in regulated industrial environments.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address demanding industrial challenges where high tensile strength and durability are non-negotiable. The steel construction combined with zinc yellow-chromate plating provides robust corrosion protection, making it suitable for outdoor machinery, construction equipment, and automotive assemblies exposed to moisture and chemicals. The 7/16-20 UNF fine thread and Class 2A thread fit ensure precise, secure fastening in applications requiring vibration resistance, such as heavy-duty frames, engine components, and structural supports. Its partial threading design allows for optimal stress distribution, reducing the risk of thread stripping under dynamic loads. By meeting ASME B18.2.1 and SAE J429 specifications, this fastener delivers reliable performance in sectors like manufacturing, transportation, and infrastructure, where compliance and safety are critical.

Specification Summary & Compliance

This fastener adheres to strict dimensional and performance standards, including Class 2A thread fit for consistent engagement and UNF fine threading with precise thread spacing. It conforms to ASME B18.2.1 for dimensional integrity and SAE J429 for material and mechanical properties, ensuring compatibility and reliability in regulated applications. The product meets common industry requirements for quality and safety, supporting use in environments where standardized components are essential.