S-91257A918 7/8"-9 x 4 1/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws
High-Strength Grade 8 Steel Hex Head Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Exceptional tensile strength of 150,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
- Superior corrosion resistance from zinc yellow-chromate plating extends service life in harsh or outdoor environments.
- High hardness rating (Rockwell C33) provides excellent wear resistance and durability under heavy loads.
- Secure and efficient installation with an external hex drive and coarse UNC threads for quick assembly and strong grip.
- Precise thread fit (Class 2A) ensures smooth engagement and consistent performance in demanding conditions.
- Partial threading design offers optimal clamping force and vibration resistance for critical joints.
- Compliance with industry standards (ASME B18.2.1, SAE J429) guarantees quality and interoperability in professional setups.
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, this Grade 8 hex head screw addresses common challenges like joint integrity and environmental wear. The steel construction combined with a zinc yellow-chromate finish provides robust protection against corrosion, making it ideal for machinery, construction, and automotive assemblies exposed to moisture or chemicals. Its coarse UNC threads and external hex drive facilitate quick, secure fastening even in high-vibration settings, reducing installation time and maintenance needs. With a partially threaded shank, it ensures precise load distribution, preventing loosening and enhancing the longevity of critical connections in structural and mechanical systems.
Specification Summary & Compliance
This screw meets Class 2A thread fit tolerances for consistent engagement and is manufactured in accordance with ASME B18.2.1 and SAE J429 specifications. It features a 7/8"-9 UNC coarse thread with a minimum thread length of 2 inches and a total length of 4 1/4 inches. The product complies with industry standards for dimensional accuracy and material properties, ensuring reliability in professional applications. Materials and processes adhere to common regulatory guidelines for quality and safety in industrial use.
