S-91253A594 5/16"-18 x 2 3/4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional strength-to-weight ratio with 130,000 psi tensile strength for reliable performance in demanding applications
• Superior corrosion resistance through black-oxide coating on alloy steel, extending service life in industrial environments
• Precise Class 3A thread fit ensures secure fastening with minimal vibration loosening in critical assemblies
• Optimized hex drive design (3/16") provides superior torque transmission and reduced cam-out risk
• 82° countersink angle creates flush surface finishes while maintaining structural integrity
• Partially threaded configuration allows for controlled clamping force and simplified alignment
• Industry compliance assurance with ASTM F835 standards and environmental regulations for global supply chain compatibility

Professional Applications & Engineering Value

Engineered for industrial machinery, heavy equipment assemblies, and structural frameworks, these black-oxide alloy steel flat head screws address critical fastening challenges where vibration resistance and corrosion protection are paramount. The UNC coarse thread design enables rapid installation in thick materials while maintaining Class 3A precision fit for vibration-prone environments. The hex drive configuration delivers maximum torque transfer efficiency, reducing installation time and tool wear. The partially threaded section provides controlled clamping force distribution, preventing joint distortion in precision assemblies. With Rockwell C39 hardness and 130,000 psi tensile strength, these fasteners withstand extreme mechanical stresses while the black-oxide surface treatment offers superior protection against industrial atmospheres and chemicals.

Specification Summary & Compliance

Manufactured to exacting Class 3A thread tolerances with UNC 5/16"-18 coarse threading and right-hand thread direction. Complies with ASTM F835 manufacturing specifications for mechanical properties and dimensional accuracy. Features 82° countersink angle and standard flat head profile for consistent seating. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial markets.