S-91771A640 3/8"-16 x 4" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with passivated 18-8 stainless steel construction for long-term reliability in harsh environments
• Superior holding power with 80,000 psi tensile strength and Rockwell B80 hardness for demanding applications
• Secure flush installation with standard flat head profile and 82° countersink angle for smooth surface finishing
• Reliable fastening performance through Class 2A thread fit and UNC coarse threads for easier alignment and reduced cross-threading
• Efficient installation with Phillips No. 4 drive design providing good torque transfer and common tool compatibility
• Optimized thread engagement with partial threading allowing unthreaded shank section for precise clamping control
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations for global project specifications

Professional Applications & Engineering Value

This 3/8"-16 UNC flat head screw delivers exceptional engineering value for 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 factors, making it ideal for marine equipment, food processing machinery, and outdoor structures. The coarse UNC threads ensure rapid installation and reliable performance in materials where fine threads might strip or fail. With partial threading, this fastener offers precise clamping force distribution, preventing joint loosening in vibrating environments. The 82° countersink angle and flat head design create seamless surface integration, essential for applications requiring aerodynamic profiles or safety considerations. These industrial fasteners solve critical challenges in assembly lines, construction projects, and heavy equipment maintenance where durability and compliance with ASME B18.6.3 standards are non-negotiable.

Specification Summary & Compliance

This 4" length flat head screw features precise Class 2A thread fit tolerance ensuring consistent engagement and reliable performance. Manufactured to UNC coarse thread standards with 3/8"-16 threading and right-hand orientation. The product strictly complies with ASME B18.6.3 mechanical specifications and demonstrates environmental responsibility through RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) compliance, meeting the latest regulatory requirements for hazardous substance restrictions.