S-91257A948 7/8"-14 x 7 1/2" 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 industrial applications
- Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
- Optimized thread engagement through UNF fine threading and Class 2A fit, ensuring vibration resistance and secure fastening
- Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated loading
- Reliable installation torque enabled by the external hex drive and substantial head dimensions (1 5/16" width)
- Versatile partial threading allowing for both clamping and alignment functions in assembled components
- Full regulatory compliance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards for global industrial use
Professional Applications & Engineering Value
This Grade 8 hex head screw delivers critical engineering solutions where high tensile strength and corrosion resistance are paramount. The 7/8"-14 UNF fine thread configuration provides superior resistance to vibrational loosening in heavy machinery, construction equipment, and structural assemblies. The partially threaded design allows the unthreaded shank to bear shear loads while the threaded portion secures components. With zinc yellow-chromate plating protecting the steel construction, these fasteners maintain performance in outdoor, marine, and chemical exposure conditions. The external hex drive and substantial head dimensions enable high torque installation, making them ideal for critical connections in manufacturing, transportation, and infrastructure projects where failure is not an option.
Specification Summary & Compliance
Manufactured to precise Class 2A thread fit tolerances with UNF fine thread spacing (14 TPI). Complies with ASME B18.2.1 and SAE J429 specifications for dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards. Features 7 1/2" length with 2 1/4" minimum thread length and external hex drive configuration for standardized tool compatibility.
