S-91257A933 7/8"-14 x 3 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 load-bearing capacity with 150,000 psi tensile strength for reliable performance in high-stress applications
- Superior corrosion resistance through zinc yellow-chromate plating that protects against harsh industrial environments
- Precise thread engagement with Class 2A UNF fine threads ensuring secure, vibration-resistant connections
- Optimized torque transmission via external hex drive design that prevents tool slippage during installation
- Enhanced durability from Rockwell C33 hardness that maintains structural integrity under repeated stress
- Versatile partial threading allowing both clamping and alignment functions in complex assemblies
- Regulatory compliance assurance meeting ASME, SAE, RoHS 3 and REACH standards for global industrial use
Professional Applications & Engineering Value
This Grade 8 hex head screw delivers critical engineering solutions for heavy machinery, structural steel connections, and industrial equipment where failure isn't an option. The 7/8"-14 UNF fine thread configuration provides superior resistance to vibrational loosening compared to coarse threads, while the partial threading design allows unthreaded shank sections to bear shear loads effectively. The zinc yellow-chromate plated steel construction creates a barrier against corrosion in outdoor or chemically aggressive environments, significantly extending service life. With external hex drive compatibility, these screws accommodate high-torque installation using standard industrial tools, making them ideal for maintenance operations and production line applications requiring reliable, high-strength fastening solutions.
Specification Summary & Compliance
Manufactured to precise Class 2A thread fit tolerances with 7/8"-14 UNF fine threading and 3 1/4" length. Complies with ASME B18.2.1 and SAE J429 Grade 8 specifications for dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards, ensuring safe use across global industrial markets.
