S-91781A578 5/16"-18 x 1/2" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance thanks to 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable performance under heavy loads
• Optimized installation efficiency through UNC coarse threading and Class 2A thread fit, ensuring quick assembly and secure fastening
• Flush, professional finish enabled by the 82° countersink angle and undercut flat head design for seamless surface integration
• Full-thread engagement along the entire 1/2" length provides maximum holding power and vibration resistance
• Regulatory compliance assurance meeting ASME B18.6.3 specifications, RoHS 3, and REACH standards for global industrial applications
• Durable slotted drive offers reliable torque transmission while maintaining the screw's structural integrity during installation

Professional Applications & Engineering Value

This 18-8 stainless steel flat head screw delivers critical engineering solutions where corrosion resistance and structural integrity are paramount. The combination of UNC coarse threading and Class 2A thread fit ensures rapid installation in manufacturing assembly lines while maintaining precise tolerances. The passivated finish significantly enhances the screw's longevity in corrosive environments including marine applications, chemical processing equipment, and outdoor machinery. The undercut flat head profile with 82° countersink angle provides superior flush mounting capabilities, eliminating protrusions in precision machinery, electronic enclosures, and automotive components where surface clearance is critical. These industrial screws are engineered to withstand vibration and thermal cycling while maintaining their clamping force integrity.

Specification Summary & Compliance

This fastener maintains precise Class 2A thread fit tolerances with UNC coarse threading (5/16"-18) and full threading along the 1/2" length. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy and performance. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and regulatory acceptance for global industrial markets.