S-91771A576 1/4"-20 x 5" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with passivated 18-8 stainless steel construction for extended service life in harsh environments
• Exceptional tensile strength of 80,000 psi ensures reliable performance under heavy loads and vibration
• Precise Class 2A thread fit provides consistent engagement and reduces cross-threading risks during installation
• Optimized Phillips No. 3 drive delivers efficient torque transfer and reduces cam-out during high-torque applications
• 82° countersink angle enables flush mounting for clean, professional finishes in visible applications
• Partial threading design allows for precise clamping force control and secure fastening in variable material thicknesses
• Full regulatory compliance with ASME B18.6.3, RoHS 3, and REACH standards ensures quality and environmental responsibility

Professional Applications & Engineering Value

These 1/4"-20 UNC flat head Phillips screws deliver critical engineering advantages for industrial applications where corrosion resistance and structural integrity are paramount. The passivated 18-8 stainless steel construction provides exceptional protection against oxidation and chemical exposure, making them ideal for marine equipment, food processing machinery, and outdoor structures. The coarse UNC threading ensures rapid installation and superior holding power in various materials, while the partially threaded design prevents over-compression in assembly applications. With Rockwell B80 hardness and 80,000 psi tensile strength, these industrial screws maintain fastener integrity under sustained vibration and dynamic loading conditions, reducing maintenance frequency and downtime in critical operations.

Specification Summary & Compliance

Manufactured to exacting ASME B18.6.3 specifications with Class 2A thread fit tolerances for precision engagement. Features 1/4"-20 UNC coarse threads with minimum 1-1/2" thread length and standard 82° countersink profile. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global markets. The passivated surface treatment enhances corrosion resistance while maintaining the mechanical properties of 18-8 stainless steel.