S-91771A889 3-48 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, ensuring long-term reliability in harsh environments
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for demanding industrial applications
• Precise flush installation featuring an 82° countersink angle and undercut head design for seamless surface finishing
• Optimized drive engagement with Phillips No. 1 drive style providing secure torque transmission and reduced cam-out risk
• Reliable thread performance through Class 2A thread fit and coarse UNC threading ensuring consistent fastening integrity
• Full-threaded design delivering maximum grip length and uniform stress distribution across the entire fastener
• Regulatory compliance assurance meeting ASME B18.6.3 specifications and environmental standards including RoHS 3 and REACH

Professional Applications & Engineering Value

These 3-48 UNC flat head screws deliver critical engineering solutions where corrosion resistance and structural integrity are paramount. The passivated 18-8 stainless steel construction provides exceptional protection against chemical exposure and atmospheric corrosion, making them ideal for industrial equipment, marine components, and outdoor machinery. The combination of 82° countersink angle and undercut head profile ensures perfect flush mounting in precision assemblies, eliminating protrusions that could interfere with moving parts. With fully threaded coarse UNC patterning and Class 2A thread fit, these fasteners maintain consistent clamping force in vibration-prone applications while the Phillips No. 1 drive facilitates efficient installation in confined spaces common in electronic enclosures and precision instruments.

Specification Summary & Compliance

Manufactured to ASME B18.6.3 specifications with Class 2A thread fit tolerance ensuring precise dimensional accuracy. The 3-48 UNC coarse thread configuration provides optimal engagement in various materials while the 82° countersink angle meets industry-standard recess requirements. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations guarantees these fasteners meet current substance restriction guidelines for industrial applications worldwide.