S-91255A583 5/16"-18 x 1" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, extending service life in harsh industrial environments
• High tensile strength (120,000 psi) ensures reliable performance under heavy loads and vibration
• Precision Class 3A thread fit provides superior engagement and reduces cross-threading risks
• Hex drive design (3/16") enables secure tool engagement and efficient installation
• Fully threaded construction maximizes grip length and load distribution across applications
• Rockwell C39 hardness maintains structural integrity and resists wear during repeated use
• Coarse UNC threading facilitates quick assembly and disassembly in various materials

Professional Applications & Engineering Value

These black-oxide alloy steel rounded head screws deliver critical advantages in demanding applications where corrosion resistance and mechanical strength are paramount. The 5/16"-18 UNC coarse thread configuration ensures rapid installation in metal assemblies, machinery, and structural frameworks, while the Class 3A thread fit guarantees precise mating with nuts and tapped holes. The button head profile provides a low-profile finish that minimizes snagging hazards in equipment with moving parts. Engineered to withstand vibration and shock loads, these fully threaded hex drive screws maintain clamp force integrity in automotive, construction, and heavy equipment applications where fastener failure is not an option.

Specification Summary & Compliance

Manufactured to exacting ASME B18.3 and ASTM F835 specifications with Class 3A thread tolerances for superior fit. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Features right-hand UNC coarse threads with 1" length and 0.313" thread diameter. The black-oxide surface treatment provides additional corrosion protection while maintaining dimensional stability.