S-91794A109 4-40 x 7/16" 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 delivering 70,000 psi tensile strength and Rockwell B55 hardness for reliable load-bearing performance
• Optimized head design featuring high, narrow fillister profile for enhanced tool engagement and reduced head protrusion
• Precision threading with Class 2A UNC coarse threads ensuring consistent fit and vibration resistance in assembly applications
• Full-threaded construction providing maximum grip length and uniform stress distribution across the entire fastener
• Regulatory compliance meeting ASME B18.6.3 standards and environmental regulations for global industrial applications
• Versatile right-hand threading compatible with standard UNC 4-40 nuts and tapped holes for broad interoperability

Professional Applications & Engineering Value

This 4-40 UNC rounded head slotted machine screw delivers critical engineering advantages through its 18-8 stainless steel composition and specialized passivated finish, providing exceptional resistance to oxidation and chemical degradation in demanding environments. The high, narrow fillister head profile offers superior driver engagement while minimizing clearance requirements, making it ideal for confined spaces in precision machinery, electronic enclosures, and industrial equipment. With coarse UNC threading and Class 2A thread fit, installation efficiency is maximized while maintaining secure fastening integrity. The combination of 70,000 psi tensile strength and full-threaded design ensures reliable performance in vibration-prone applications, reducing maintenance frequency and downtime in continuous operation settings.

Specification Summary & Compliance

This fastener maintains Class 2A thread fit tolerance per UNC standards with 4-40 thread size and coarse thread spacing. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy and performance. The screw is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental regulations for hazardous substance restrictions.