S-91613A432 4-40 x 1/4" ASME B18.6.3 Stainless Steel Fillister Head Slotted Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance from 316 Stainless Steel construction with passivated finish, ideal for harsh industrial environments
• High tensile strength of 100,000 psi ensures reliable performance under demanding mechanical loads
• Precision Class 2A thread fit provides consistent engagement and vibration resistance in assembly applications
• Optimized fillister head design with high, narrow profile offers superior clearance and seating in confined spaces
• Slotted drive compatibility enables straightforward installation with standard tools while maintaining head integrity
• Full threading along 1/4" length delivers maximum grip and load distribution across the entire fastener
• Regulatory compliance assurance meets ASME B18.6.3, RoHS 3, and REACH standards for global industrial acceptance

Professional Applications & Engineering Value

Engineered for precision machinery and demanding industrial applications, these 4-40 UNC rounded head screws address critical challenges in corrosive environments. The 316 Stainless Steel composition combined with passivated surface treatment creates a robust barrier against chemical exposure and atmospheric degradation, significantly extending service life in marine, chemical processing, and food-grade applications. The high, narrow fillister head profile provides enhanced clearance for tight-tolerance assemblies while maintaining substantial bearing surface. With coarse UNC threading and Class 2A fit, these fasteners deliver reliable engagement in both soft and hard materials, reducing cross-threading risks during high-volume production. The combination of 100,000 psi tensile strength and Rockwell B100 hardness ensures dimensional stability under vibration and thermal cycling, making them ideal for precision equipment, instrumentation, and critical mechanical assemblies where fastener failure is not an option.

Specification Summary & Compliance

This 4-40 UNC screw features precision Class 2A thread fit with coarse thread spacing, manufactured to exacting dimensional standards. The fastener maintains full compliance with ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Environmental and safety compliance is assured through RoHS 3 (2015/863/EU) adherence and REACH (EC 1907/2006) conformity, validating its suitability for regulated industries and international markets. The complete threading along the 1/4" length ensures consistent performance across the entire engagement area.