S-91773A109 4-40 x 7/16" ASME B18.6.3 Stainless Steel Round Head Phillips 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 with 100,000 psi tensile strength and Rockwell B100 hardness for reliable performance under heavy loads
• Optimized driving efficiency through No. 1 Phillips drive design that prevents cam-out and ensures secure installation
• Enhanced holding power from fully threaded coarse spacing (UNC) that provides maximum engagement and vibration resistance
• Precision manufacturing with Class 2A thread fit ensuring consistent performance and easy assembly in industrial applications
• Regulatory compliance meeting ASME B18.6.3 specifications plus RoHS 3 and REACH environmental standards
• Versatile rounded head design offering smooth surface profile that minimizes snagging and provides clean aesthetic finish

Professional Applications & Engineering Value

These 4-40 UNC rounded head Phillips screws deliver critical engineering solutions where corrosion resistance and mechanical reliability are paramount. The 18-8 stainless steel composition combined with passivated finish creates a protective barrier against oxidation, moisture, and chemical exposure, making them ideal for industrial equipment, electronic enclosures, and marine applications. The fully threaded coarse spacing ensures maximum material engagement in both metals and plastics, while the rounded head profile eliminates sharp edges that could damage wiring or components. With 100,000 psi tensile strength, these machine screws maintain structural integrity in high-vibration environments, providing engineers with a dependable fastening solution that meets rigorous ASME B18.6.3 standards for dimensional accuracy and performance.

Specification Summary & Compliance

Manufactured to precise Class 2A thread fit tolerances with UNC coarse thread spacing (4-40 size) and 7/16" length. Complies with ASME B18.6.3 mechanical standards for dimensional consistency and performance. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance requirements, ensuring safe use in regulated industries. Threading is fully threaded with right-hand direction and features a standard rounded head profile with 0.211" head diameter.