S-91253A576 5/16"-18 x 3/8" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, ideal for harsh industrial environments
• Superior torque transmission through hex drive design prevents stripping during high-torque installation
• Maximum thread engagement with fully threaded Class 3A UNC coarse threads ensures reliable fastening
• High-strength performance with 130,000 psi tensile strength and Rockwell C39 hardness for heavy-duty applications
• Precise flush mounting with standard 82° countersink angle for clean, professional installations
• Regulatory compliance assurance meeting ASTM F835, RoHS 3, and REACH standards for global industrial use
• Optimized for efficiency with coarse thread spacing enabling faster assembly in production environments

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these 5/16"-18 UNC flat head screws provide critical solutions for machinery assembly, structural frameworks, and heavy equipment manufacturing. The black-oxide alloy steel construction delivers superior corrosion protection in environments where moisture and chemicals are present, while the hex drive design ensures secure installation without cam-out issues common in high-torque scenarios. The Class 3A thread fit guarantees precise engagement with mating components, reducing the risk of vibration-induced loosening in dynamic applications. With 130,000 psi tensile strength and full threading, these flat head hex drive screws maintain structural integrity under extreme loads, making them ideal for automotive, construction, and industrial machinery where reliability is paramount.

Specification Summary & Compliance

This 5/16"-18 UNC flat head screw features precision Class 3A thread fit with coarse thread spacing for optimal engagement. Manufacturing complies with ASTM F835 specifications for dimensional accuracy and performance standards. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and regulatory acceptance for international industrial applications. The black-oxide surface treatment provides consistent corrosion protection while maintaining the alloy steel's mechanical properties across the specified 3/8" length and 0.656" head diameter configuration.