S-91257A664 3/8"-24 x 3 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
- Maximum load-bearing capability with 150,000 psi tensile strength and Grade 8 classification for critical heavy-duty applications
- Superior corrosion protection through zinc yellow-chromate plating that extends service life in harsh environments
- Precise thread engagement with Class 2A fit and UNF fine threading for secure, vibration-resistant connections
- Optimized torque transmission via external hex drive and 9/16" head width for efficient installation with standard tools
- Enhanced durability from Rockwell C33 hardness that maintains structural integrity under extreme stress
- Versatile partial threading allowing unthreaded shank sections for precise clamping in machinery assemblies
- Regulatory compliance assurance meeting ASME, SAE, RoHS 3, and REACH standards for global industrial use
Professional Applications & Engineering Value
These Grade 8 hex head screws deliver exceptional engineering value in demanding applications where failure isn't an option. The steel construction with zinc yellow-chromate plating provides critical corrosion resistance for outdoor machinery, construction equipment, and industrial assemblies exposed to moisture and chemicals. The 3/8"-24 UNF fine threading with Class 2A fit ensures precise engagement in tapped holes, reducing the risk of stripping while maintaining vibration resistance in dynamic load conditions. The partially threaded design allows the unthreaded shank to bear against mating surfaces, preventing loosening under shear forces. With 150,000 psi tensile strength, these heavy-duty screws are engineered to withstand extreme tension in structural connections, vehicle frames, and high-pressure equipment where reliability is paramount.
Specification Summary & Compliance
This 3/8"-24 x 3-1/2" hex head screw features Class 2A thread fit tolerance and UNF fine threading with minimum 1" thread length. Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and mechanical properties. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for safe industrial use worldwide.
