S-91794A557 1/4"-28 x 1/2" ASME B18.6.3 Stainless Steel Fillister Head Slotted Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance from 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for reliable, long-term performance
• Precise thread engagement with Class 2A fit and UNF fine threading ensures secure fastening in critical applications
• Optimized head design featuring a high, narrow fillister profile for enhanced tool clearance and professional appearance
• Full threading along 1/2" length provides maximum grip and load distribution across the entire fastener
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations including RoHS 3 and REACH
• Slotted drive compatibility with standard tools for straightforward installation and maintenance operations

Professional Applications & Engineering Value

This 1/4"-28 UNF fillister head slotted screw delivers exceptional engineering value in demanding industrial applications where corrosion resistance and mechanical reliability are paramount. The combination of 18-8 stainless steel material and passivated finish creates a robust barrier against oxidation and chemical exposure, making it ideal for machinery, electronic enclosures, and marine equipment. The high, narrow fillister head profile provides superior clearance for tools and components while maintaining an aesthetically pleasing industrial appearance. With fine thread spacing and Class 2A thread fit, these screws ensure precise alignment and vibration resistance in assemblies requiring repeated maintenance or exposure to dynamic loads. The fully threaded design maximizes contact surface area, distributing stress evenly across the entire 1/2" length for enhanced joint integrity.

Specification Summary & Compliance

This fastener maintains Class 2A thread fit tolerance with UNF (Unified National Fine) 1/4"-28 threading and right-hand thread direction. Manufacturing conforms to ASME B18.6.3 specifications for dimensional accuracy and performance standards. The screw is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across various industrial sectors. Critical dimensions include 0.414" head diameter, 0.237" head height, and 1/2" overall length with complete threading.