S-91781A640 3/8"-16 x 4" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel and passivated finish, ensuring longevity in harsh environments
• Exceptional mechanical strength offering 80,000 psi tensile strength and Rockwell B80 hardness for reliable load-bearing performance
• Precision thread fit with Class 2A UNC coarse threads providing secure, vibration-resistant fastening in industrial assemblies
• Optimized partial threading design allowing controlled clamping force and reduced risk of cross-threading during installation
• Flush mounting capability with 82° countersink angle and standard flat head profile for seamless surface integration
• Regulatory compliance assurance meeting ASME B18.6.3 manufacturing standards and environmental regulations (RoHS 3 & REACH)
• Universal compatibility with right-hand UNC coarse threads (3/8"-16) ensuring broad interchangeability across industrial equipment

Professional Applications & Engineering Value

Engineered for demanding industrial environments, these 3/8"-16 UNC flat head screws solve critical fastening challenges where corrosion resistance and structural integrity are paramount. The 18-8 stainless steel construction with passivated finish provides inherent protection against chemical exposure and atmospheric corrosion, making them ideal for marine equipment, food processing machinery, and outdoor structural applications. The partially threaded design concentrates engagement strength where needed while preventing thread interference in clearance holes. With ASME B18.6.3 compliance ensuring dimensional precision, these flat head screws deliver consistent performance in countersunk applications across metal fabrication, heavy machinery, and transportation equipment where vibration resistance and flush surface requirements are critical.

Specification Summary & Compliance

Manufactured to exacting ASME B18.6.3 specifications with Class 2A thread fit tolerance for consistent engagement. Features UNC coarse threads (3/8"-16) with right-hand direction and standard 82° countersink angle. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across regulated industries.