S-91771A935 4-40 x 5/16" 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, ideal for harsh industrial environments
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable load-bearing performance
• Precise thread engagement through Class 2A thread fit and UNC coarse threading, ensuring secure fastening in various materials
• Optimized flush mounting with standard flat head profile and 100° countersink angle for seamless surface integration
• Efficient installation using Phillips No. 1 drive, providing good torque transfer and reduced cam-out risk
• Full-threaded design offering maximum grip length and uniform stress distribution along the entire 5/16" length
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations for global supply chain compatibility

Professional Applications & Engineering Value

This 4-40 UNC flat head screw delivers critical engineering advantages in demanding applications where corrosion resistance and precise flush mounting are paramount. The passivated 18-8 stainless steel construction provides excellent protection against oxidation and chemical exposure, making these flat head screws ideal for electronics enclosures, machinery panels, and marine equipment. The combination of UNC coarse threads and Class 2A thread fit ensures rapid installation and reliable holding power in both metallic and composite materials. The 100° countersink angle and standardized head profile prevent component interference while maintaining structural integrity under vibration. These industrial fasteners solve common challenges of material compatibility, installation efficiency, and long-term reliability in OEM manufacturing and maintenance operations.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit and UNC coarse thread specifications. Complies with ASME B18.6.3 mechanical standards for dimensional consistency and performance. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance requirements, ensuring suitability for regulated industries and international markets.