S-91263A725 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 zinc plating that protects against rust and extends service life in demanding environments
• Superior tensile strength of 130,000 psi ensures reliable performance under heavy loads and prevents fastener failure
• Precision Class 3A thread fit provides consistent, secure engagement with mating components for vibration-resistant assemblies
• 82° countersink angle design allows for flush mounting in standard countersunk holes, creating smooth, professional-looking surfaces
• Hex drive compatibility enables high-torque installation with common tools, reducing assembly time and labor costs
• Full threading along entire shank length maximizes grip strength and distributes clamping force evenly across the joint
• Comprehensive compliance certification including ASTM F835, RoHS 3, and REACH ensures material quality and environmental responsibility

Professional Applications & Engineering Value

These 5/16"-18 UNC flat head screws deliver critical engineering solutions where high-strength fastening and flush surface requirements intersect. The zinc-plated alloy steel construction provides essential corrosion protection for industrial equipment, machinery frames, and structural assemblies exposed to harsh operating conditions. With their coarse UNC threads and Class 3A fit, these screws resist loosening from vibration while ensuring rapid installation in production environments. The 82° countersink angle perfectly mates with standard chamfered holes, eliminating protrusions that could interfere with moving parts or create safety hazards. These fully threaded fasteners are particularly valuable in heavy-duty applications where maximum thread engagement is necessary to withstand extreme mechanical stresses and maintain joint integrity over time.

Specification Summary & Compliance

These flat head screws feature precision 5/16"-18 UNC coarse threads with Class 3A fit for consistent assembly performance. Manufacturing complies with ASTM F835 specifications for mechanical properties and dimensional accuracy. The fasteners are certified RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international standards for restricted substances and chemical safety. With a Rockwell C39 hardness rating and 130,000 psi tensile strength, these screws deliver reliable performance in demanding industrial applications while maintaining full regulatory compliance.