S-91257A474 3/8"-24 x 7" 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 load-bearing capacity with 150,000 psi tensile strength, ideal for high-stress structural connections
- Superior corrosion resistance through zinc yellow-chromate plating, extending service life in harsh environments
- Precise torque transmission with external hex drive and 9/16" head width for secure installation
- Optimized thread engagement through UNF fine spacing and Class 2A fit, reducing vibration loosening
- Controlled thread application with partial threading, preventing over-tightening in deep assemblies
- Certified material integrity with Grade 8 classification and Rockwell C33 hardness for consistent performance
- Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for quality assurance
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, this Grade 8 hex head screw delivers reliable performance in construction machinery, automotive assemblies, and structural steel frameworks. The 3/8"-24 UNF fine thread configuration provides superior resistance to vibrational loosening compared to coarse threads, while the partial threading design allows for precise clamp load distribution. The zinc yellow-chromate plating creates a protective barrier against oxidation and chemical exposure, significantly extending maintenance intervals in outdoor or corrosive environments. With its 7-inch length and external hex drive, this high-strength fastener enables efficient installation in deep or confined spaces where standard fasteners would fail.
Specification Summary & Compliance
Manufactured to ASME B18.2.1 and SAE J429 specifications with Class 2A thread fit tolerance ensuring consistent mating with standard nuts. The inch system measurement and UNF thread type maintain compatibility with North American industrial standards. Material certification includes Grade 8 strength classification with verified Rockwell C33 hardness and 150,000 psi tensile strength. Surface treatment complies with industry corrosion protection requirements while maintaining dimensional accuracy across the 1 1/4" minimum thread length and 7" overall length.
