S-91257A614 5/16"-24 x 2 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
- Maximum load-bearing capability with 150,000 psi tensile strength for critical structural applications
- Superior corrosion protection through zinc yellow-chromate plating that withstands harsh industrial environments
- Precise thread engagement with Class 2A fit and UNF fine threads ensuring vibration resistance and secure fastening
- Enhanced durability from Rockwell C33 hardness that maintains integrity under repeated stress
- Optimized partial threading providing both gripping power and clearance where needed
- Heavy-duty performance meeting Grade 8 specifications for the most demanding mechanical applications
- External hex drive compatibility with standard tools for quick installation and maintenance
Professional Applications & Engineering Value
Engineered for heavy machinery, construction equipment, and automotive assemblies, these Grade 8 hex head screws solve critical fastening challenges where failure is not an option. The 5/16"-24 UNF fine thread configuration delivers superior resistance to vibrational loosening while maintaining precise clamping force. Partially threaded design allows for controlled tension distribution, preventing stress concentration in sensitive components. The zinc yellow-chromate plating provides exceptional corrosion resistance in outdoor or chemically aggressive environments, significantly extending service life. With 2 1/4" length and external hex drive, these fasteners offer both deep penetration capability and straightforward installation using standard industrial tools.
Specification Summary & Compliance
Manufactured to exacting Class 2A thread fit tolerances with UNF thread form ensuring consistent performance. Complies with ASME B18.2.1 and SAE J429 Grade 8 specifications for dimensional accuracy and mechanical properties. Meets environmental standards including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, ensuring safe use across regulated industries.
