S-91794A117 4-40 x 1 1/4" ASME B18.6.3 Stainless Steel Fillister Head Slotted Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish for extended service life in harsh environments
• Exceptional mechanical strength offering 70,000 psi tensile strength and Rockwell B55 hardness for reliable load-bearing performance
• Optimized head design featuring a high, narrow rounded fillister profile for enhanced clearance and professional appearance
• Precision threading with Class 2A UNC coarse threads ensuring secure fastening and vibration resistance in industrial assemblies
• Full-threaded construction providing maximum grip length and uniform stress distribution across the entire 1-1/4" length
• Broad compliance coverage meeting ASME B18.6.3 specifications plus RoHS 3 and REACH environmental regulations
• Traditional slotted drive allowing compatibility with standard tools while maintaining the classic fillister head aesthetic

Professional Applications & Engineering Value

This 4-40 UNC rounded fillister head slotted screw delivers critical performance advantages for precision assemblies requiring both aesthetic appeal and mechanical reliability. The 18-8 stainless steel composition combined with passivated finish creates a robust barrier against corrosion, making it ideal for electrical enclosures, instrumentation, and marine applications where moisture resistance is essential. The high, narrow head profile provides superior clearance in counterbored holes while maintaining substantial bearing surface. With coarse thread spacing and Class 2A thread fit, installation is streamlined with reduced cross-threading risk, particularly beneficial in high-volume production environments. The fully threaded design ensures consistent clamping force distribution, preventing joint loosening under vibration - a common challenge in industrial machinery and transportation equipment.

Specification Summary & Compliance

This precision fastener maintains Class 2A thread tolerances per UNC standards with coarse thread spacing, ensuring consistent mating with corresponding nuts and tapped holes. Manufacturing strictly adheres to ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Environmental compliance is verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) certifications, confirming the absence of restricted substances. The combination of 70,000 psi tensile strength and Rockwell B55 hardness provides documented performance metrics for engineering calculations and quality assurance protocols.