S-91771A853 1/4"-20 x 7/16" 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
• Optimized flush mounting featuring an undercut flat head with 82° countersink angle for seamless surface integration
• Enhanced driving efficiency with Phillips No. 3 drive design for secure torque transmission and reduced cam-out risk
• Precision thread engagement through Class 2A thread fit and coarse UNC pattern ensuring consistent fastening performance
• Full-threaded design providing maximum grip length and uniform stress distribution across connected materials
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

These passivated 18-8 stainless steel flat head screws deliver critical performance advantages in demanding industrial applications where corrosion resistance and structural integrity are paramount. The undercut flat head profile with 82° countersink angle enables perfect flush mounting in precision machinery, electronic enclosures, and automotive assemblies, eliminating protrusions that could interfere with moving components. The fully threaded UNC coarse pattern combined with Class 2A thread fit ensures rapid installation and vibration-resistant fastening in materials ranging from metals to high-density plastics. With exceptional 80,000 psi tensile strength, these Phillips drive screws maintain clamping force under dynamic loads while the passivated surface treatment provides lasting protection against chemical exposure and environmental degradation in manufacturing facilities, marine applications, and outdoor equipment.

Specification Summary & Compliance

Manufactured to exacting dimensional standards with Class 2A thread fit tolerance for consistent engagement. Thread specifications include 1/4"-20 UNC coarse thread pattern with right-hand direction. Full compliance with ASME B18.6.3 mechanical standards for dimensional uniformity and performance reliability. Meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance for restricted substance control. All specifications verified for industrial deployment and quality assurance.