S-91257A947 7/8"-14 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 capability with 150,000 psi tensile strength for demanding industrial applications
- Superior corrosion resistance through zinc yellow-chromate plating that protects against harsh environmental conditions
- Precise thread engagement with Class 2A UNF fine threads ensuring reliable fastening and vibration resistance
- Optimized torque transmission via external hex drive design that prevents tool slippage during installation
- Enhanced durability from Rockwell C33 hardness rating that maintains structural integrity under stress
- Controlled thread engagement through partial threading that concentrates strength where needed most
- 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 performance in heavy machinery, structural steel connections, and high-vibration environments where failure isn't an option. The 7/8"-14 UNF fine thread configuration provides superior clamping force distribution compared to coarse threads, while the partial threading design prevents thread damage during assembly and concentrates stress away from the shank. The zinc yellow-chromate plating creates a sacrificial barrier that significantly extends service life in corrosive conditions, making it ideal for outdoor equipment, marine applications, and industrial manufacturing. With its external hex drive and substantial 1 5/16" head width, installers achieve maximum torque application without compromising fastener integrity.
Specification Summary & Compliance
Manufactured to exacting Class 2A thread fit tolerances with UNF (Unified National Fine) thread form ensuring precise mating with corresponding nuts. Complies with ASME B18.2.1 dimensional specifications and SAE J429 Grade 8 mechanical properties, guaranteeing consistent performance across applications. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards, making this fastener suitable for regulated industries worldwide. The 7" length with 2 1/4" minimum thread length provides optimal engagement depth for critical connections.
