S-91253A373 1/2"-20 x 1" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating on alloy steel for extended service life in demanding environments
• Exceptional mechanical strength with 130,000 psi tensile strength and Rockwell C39 hardness for high-stress applications
• Precision thread engagement with Class 3A fit and UNF fine threads ensuring vibration resistance and reliable fastening
• Optimized installation efficiency through 5/16" hex drive design providing secure tool engagement and torque transmission
• Flush mounting capability with standard 82° countersink angle for seamless surface integration in assembled components
• Full thread coverage along the 1" length maximizes grip strength and load distribution across connected materials
• Regulatory compliance assurance meeting ASME B18.3, ASTM F835, RoHS 3, and REACH standards for global industrial use

Professional Applications & Engineering Value

Engineered for high-performance industrial fastening, these black-oxide alloy steel flat head screws address critical challenges in machinery assembly, automotive manufacturing, and heavy equipment applications. The UNF fine thread configuration (1/2"-20) combined with Class 3A thread fit delivers superior vibration resistance, preventing loosening in dynamic operating conditions. The 82° countersink angle ensures flush mounting in precision-machined components, while the 5/16" hex drive facilitates high-torque installation without cam-out. The black-oxide surface treatment provides essential corrosion protection in environments exposed to moisture, oils, and industrial chemicals, making these fully threaded screws ideal for permanent assemblies requiring 130,000 psi tensile strength and long-term reliability.

Specification Summary & Compliance

Manufactured to exacting standards with Class 3A thread precision per UNF specifications, ensuring consistent fit and performance. Complies with ASME B18.3 dimensional requirements and ASTM F835 mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards. Thread specifications include right-hand direction, fine spacing, and 0.5" major diameter. Hardness maintained at Rockwell C39 with full threading along the 1" length for maximum load-bearing capacity.