S-91263A574 5/16"-18 x 7/8" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating that protects against rust and extends service life in demanding environments
• Exceptional tensile strength of 130,000 psi ensures reliable performance under high-stress conditions and prevents fastener failure
• Precise Class 3A thread fit provides tighter tolerances for secure mating with nuts and threaded components, reducing vibration loosening
• 82° countersink angle allows for flush mounting in standard countersunk holes, creating smooth surfaces and improved aesthetics
• Hex drive design enables high-torque installation with common tools, speeding up assembly while minimizing stripping risks
• Full threading along the 7/8" length offers maximum grip and adjustment flexibility in various material thicknesses
• Compliance with ASTM F835, RoHS 3, and REACH ensures material safety, environmental responsibility, and consistent quality for industrial applications

Professional Applications & Engineering Value

These 5/16"-18 UNC flat head screws are engineered to address critical challenges in industrial assembly, where vibration resistance, material compatibility, and long-term reliability are paramount. The zinc-plated alloy steel construction provides excellent corrosion protection for outdoor equipment, machinery, and structural frameworks exposed to harsh conditions. With a Rockwell C39 hardness and 130,000 psi tensile strength, they withstand heavy loads and dynamic stresses without deformation. The coarse UNC threads and Class 3A fit ensure quick installation and secure fastening in metals, plastics, and composites, reducing maintenance cycles. Ideal for automotive, construction, and manufacturing sectors, these fully threaded screws with hex drive simplify repairs and upgrades while meeting stringent ASTM F835 specifications for performance and safety.

Specification Summary & Compliance

These screws feature a 5/16"-18 UNC coarse thread with Class 3A thread fit for precise dimensional accuracy and a standard 82° countersink angle. Manufactured from alloy steel with zinc plating, they comply with ASTM F835 standards for mechanical properties and are verified to be RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, ensuring adherence to environmental and safety regulations.