S-91771A592 5/16"-18 x 2 1/4" 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 long-lasting performance in harsh environments
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable load-bearing applications
• Precise flush mounting with standard 82° countersink angle and flat head design for seamless surface integration
• Optimized drive engagement through Phillips No. 4 drive style ensuring secure installation and reduced cam-out risk
• Reliable thread performance with UNC coarse threads and Class 2A fit providing vibration resistance and easy assembly
• Enhanced installation efficiency through partial threading design reducing friction and speeding up assembly processes
• Regulatory compliance assurance meeting ASME B18.6.3 standards while being RoHS 3 and REACH compliant for global applications

Professional Applications & Engineering Value

These 5/16"-18 UNC flat head screws deliver exceptional engineering value across industrial applications where corrosion resistance and structural integrity are paramount. The passivated 18-8 stainless steel construction provides superior protection against chemical exposure and environmental degradation, making them ideal for marine equipment, food processing machinery, and outdoor structural assemblies. The partially threaded design minimizes thread engagement friction while maintaining full clamping force, significantly reducing installation time in high-volume manufacturing. With their 82° countersink angle and flat head profile, these Phillips drive screws create flush surfaces that prevent snagging in conveyor systems, automotive panels, and electronic enclosures. The coarse UNC threading ensures rapid assembly in wood, plastic, and soft metal substrates while maintaining vibration resistance critical for machinery subjected to dynamic loads.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerance ensuring consistent mating with standard nuts and threaded holes. These flat head screws feature 5/16"-18 UNC coarse threads with minimum thread length of 1-1/2" and overall length of 2-1/4". Full compliance with ASME B18.6.3 manufacturing specifications guarantees dimensional accuracy and performance reliability. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring safe use across global markets without hazardous substance restrictions.