S-91770A090 4-40 x 3/16" ASME B18.6.3 Stainless Steel Truss Head Phillips Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with passivated 18-8 stainless steel construction for long-lasting performance in harsh environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B70 hardness to withstand high-stress applications
• Optimized load distribution thanks to the wide truss head design that provides superior clamping force and surface contact
• Reliable installation efficiency with Phillips No. 1 drive system ensuring secure tool engagement and reduced cam-out
• Precision thread performance featuring Class 2A thread fit and UNC coarse threads for quick assembly and vibration resistance
• Full thread engagement capability along the entire 3/16" length for maximum holding power in various material thicknesses
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations for global industrial use

Professional Applications & Engineering Value

These 4-40 UNC rounded truss head screws deliver exceptional engineering value across industrial applications where corrosion resistance and reliable fastening are critical. The passivated 18-8 stainless steel construction provides superior protection against oxidation and chemical exposure, making them ideal for electronics enclosures, machinery panels, and outdoor equipment. The unique truss head profile offers significantly larger bearing surface than standard heads, distributing clamp load effectively to prevent material damage while maintaining secure fastening. With coarse UNC threading and Class 2A thread fit, these screws ensure rapid installation and excellent vibration resistance in sheet metal, plastics, and composite materials. The combination of 70,000 psi tensile strength and fully threaded design provides maximum pull-out resistance in shallow engagement scenarios common in compact assemblies and precision instruments.

Specification Summary & Compliance

These rounded truss head screws feature precision 4-40 UNC coarse threads with Class 2A thread fit tolerances ensuring consistent performance across industrial applications. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming restriction of hazardous substances. The inch system measurements maintain 0.257" head diameter and 3/16" length with Phillips No. 1 drive configuration for standardized tool compatibility.