S-91099A160 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 delivering 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
• Flush mounting capability featuring an 82° countersink angle and undercut flat head design for seamless surface integration
• Optimized drive efficiency with Phillips No. 1 drive providing consistent torque transfer during installation
• Full threading coverage across the 5/16" length for maximum grip strength in various material thicknesses
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations for global industrial use

Professional Applications & Engineering Value

These 4-40 UNC flat head screws deliver critical engineering advantages in precision assembly applications. The passivated 18-8 stainless steel construction provides exceptional corrosion resistance, making them suitable for demanding environments including marine equipment, food processing machinery, and outdoor industrial installations. The combination of 80,000 psi tensile strength and Class 2A thread fit ensures reliable performance in vibration-prone applications while maintaining dimensional accuracy. The undercut flat head profile with 82° countersink angle allows for flush mounting in precision machinery, electronic enclosures, and automotive components where surface clearance is critical. The fully threaded design and coarse UNC threading provide superior holding power across various material densities from aluminum castings to composite panels.

Specification Summary & Compliance

Manufactured to exacting ASME B18.6.3 specifications with Class 2A thread fit tolerance for precision assembly. The UNC coarse thread (4-40) provides optimal engagement in various materials. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Mechanical properties include Rockwell B80 hardness and 80,000 psi tensile strength with complete 82° countersink angle specification for proper seating in standard countersunk holes.