S-91781A126 5-40 x 3/8" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments
• Superior mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable load-bearing performance
• Precision thread engagement featuring Class 2A thread fit and UNC coarse threads for secure fastening and vibration resistance
• Optimized flush mounting with standard 82° countersink angle and flat head design for seamless surface integration
• Full-threaded reliability ensuring maximum grip length and uniform stress distribution across applications
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations including RoHS 3 and REACH
• Simplified installation with slotted drive design accommodating standard screwdriver tools for efficient assembly

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these 5-40 UNC flat head screws deliver critical performance advantages where corrosion resistance and mechanical reliability are paramount. The 18-8 stainless steel composition combined with passivated finish provides exceptional protection against chemical exposure and atmospheric corrosion, making them ideal for marine equipment, food processing machinery, and outdoor structural assemblies. The Class 2A thread fit and coarse UNC threading ensure rapid installation and maintain secure fastening under vibration, while the 82° countersink angle enables flush mounting in precision-machined components. These fully threaded flat head screws offer consistent clamping force distribution, preventing joint loosening in critical mechanical systems and electronic enclosures where reliability cannot be compromised.

Specification Summary & Compliance

Manufactured to exacting dimensional standards with Class 2A thread fit tolerance and UNC coarse thread profile (5-40 thread size). Compliant with ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Meets environmental regulations including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) requirements for restricted substances. The 3/8" length and standard flat head profile ensure interchangeability with existing industrial fastening systems.