S-91286A177 5/16"-18 x 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 capability with 150,000 PSI tensile strength for reliable performance in high-stress applications
- Superior corrosion resistance provided by zinc-flake coating, extending service life in harsh industrial environments
- Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated stress
- Secure fastening performance through Class 2A thread fit and UNC coarse threading for vibration resistance
- Optimized installation efficiency with external hex drive design allowing high torque application
- Partial threading design enabling precise clamping force distribution across connected materials
- Regulatory compliance assurance meeting ASME, SAE, RoHS 3 and REACH standards for quality and environmental safety
Professional Applications & Engineering Value
These Grade 8 hex head screws deliver critical engineering solutions for heavy machinery, structural assemblies, and industrial equipment where high tensile strength and corrosion resistance are paramount. The zinc-flake coated steel construction provides superior protection against environmental degradation, while the 5/16"-18 UNC coarse thread configuration ensures rapid installation and reliable performance in vibration-prone applications. The partially threaded design allows for precise clamping force distribution, making these external hex drive fasteners ideal for critical joints in construction, automotive, and manufacturing sectors where failure is not an option. Their 4-inch length and Class 2A thread fit provide consistent performance across demanding industrial applications.
Specification Summary & Compliance
Manufactured to precise dimensional standards with Class 2A thread fit and UNC thread form ensuring interchangeability and reliable performance. 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) compliance requirements for environmental safety and restricted substance management. The inch system measurement and coarse thread spacing provide optimal performance in industrial fastening applications requiring high strength and durability.
