S-92949A858 5/16"-18 x 3 1/4" ASME B18.3, ASTM F879 Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish for long-lasting performance in harsh environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for reliable load-bearing capability
• Precision thread engagement with Class 3A UNC coarse threads ensuring secure fastening and vibration resistance
• Optimized installation efficiency through hex drive design providing superior torque transmission and slip resistance
• Full thread coverage along the entire 3 1/4" length for maximum grip and distribution of clamping forces
• Regulatory compliance assurance meeting ASME B18.3 specifications and environmental standards including RoHS 3 and REACH
• Rounded head design with 0.547" diameter offering smooth surface finish and reduced risk of snagging

Professional Applications & Engineering Value

This 18-8 stainless steel rounded head screw delivers critical performance advantages for demanding industrial applications where corrosion resistance and mechanical reliability are paramount. The combination of Class 3A UNC coarse threading and fully threaded design ensures maximum engagement strength in materials prone to vibration loosening, while the passivated finish provides enhanced protection against chemical exposure and environmental degradation. The hex drive configuration allows for high-torque installation in confined spaces, making it ideal for machinery assembly, structural frameworks, and heavy equipment maintenance. Engineered to withstand rigorous operating conditions, this fastener addresses common failure points in industrial settings through its 70,000 psi tensile strength and precision manufacturing compliant with ASME B18.3 standards.

Specification Summary & Compliance

Manufactured to exacting dimensional standards with Class 3A thread fit and UNC coarse thread profile (5/16"-18), this fastener ensures precise mating with corresponding components. The screw conforms to ASME B18.3 specifications (ASTM F879) and demonstrates compliance with environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006). Critical dimensions include 3 1/4" length, 0.547" head diameter, and 3/16" hex drive size, maintaining consistent quality across production batches for reliable integration into industrial assemblies.