S-91771A110 4-40 x 1/2" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance from passivated 18-8 stainless steel construction, ideal for harsh industrial environments
• Exceptional mechanical strength with 80,000 PSI tensile strength and Rockwell B80 hardness for reliable load-bearing performance
• Precision thread engagement with Class 2A UNC coarse threads ensuring secure fastening and vibration resistance
• Optimal flush mounting featuring standard 82° countersink angle for seamless surface integration
• Enhanced drive stability with Phillips No. 1 drive preventing cam-out during high-torque installation
• Full-threaded design maximizing grip length and distribution across the entire 1/2" shaft
• Regulatory compliance meeting ASME B18.6.3, RoHS 3, and REACH standards for global industrial applications

Professional Applications & Engineering Value

Engineered for demanding industrial assemblies, these 4-40 UNC flat head screws deliver critical performance where corrosion resistance and structural integrity are paramount. The passivated 18-8 stainless steel construction effectively counters chemical exposure and oxidation in manufacturing, electronics, and marine environments. The fully threaded coarse UNC pattern with Class 2A fit ensures rapid installation and consistent clamping force, while the 82° countersink enables flush mounting in precision machinery and enclosures. These Phillips drive screws maintain 80,000 PSI tensile strength under dynamic loads, making them ideal for vibration-prone applications where fastener failure is not an option.

Specification Summary & Compliance

Manufactured to ASME B18.6.3 specifications with Class 2A thread fit and UNC coarse threading. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Standard 82° flat head profile with right-hand thread direction and 1/2" length.