S-91770A874 5/16"-18 x 4" 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, ideal for harsh industrial environments and washdown applications
• Exceptional load-bearing capability from 70,000 psi tensile strength and Rockwell B70 hardness, ensuring reliable performance under stress
• Enhanced surface contact and vibration resistance with wide truss head design, distributing clamping force over a larger area
• Quick installation and removal with Phillips No. 4 drive and coarse UNC threading, reducing assembly time and labor costs
• Secure fastening with precision fit through Class 2A thread tolerance, minimizing cross-threading and ensuring consistent engagement
• Optimized thread engagement control with partial threading design, preventing over-tightening in deep material applications
• Compliance with global environmental standards including RoHS 3 and REACH, ensuring safe use across regulated industries

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these rounded truss head screws provide critical solutions for assembly challenges where surface marring and vibration loosening are common concerns. The passivated 18-8 stainless steel construction delivers exceptional corrosion resistance, making these fasteners ideal for food processing equipment, marine components, and outdoor machinery exposed to moisture and chemicals. The unique truss head profile offers a wider bearing surface than standard round heads, distributing clamping force more effectively across softer materials or larger clearance holes. Combined with coarse UNC threading and partial threading, these screws ensure rapid installation in production environments while preventing thread damage in deep-tapped holes. The Phillips No. 4 drive provides sufficient torque transmission for secure fastening without specialized tools, streamlining maintenance and repair operations across manufacturing, construction, and transportation sectors.

Specification Summary & Compliance

These 5/16"-18 UNC screws maintain precise Class 2A thread fit tolerances for consistent engagement and reliable performance. Manufactured in compliance with ASME B18.6.3 specifications, they ensure dimensional accuracy and mechanical properties meeting industrial standards. Environmental compliance is verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) certifications, confirming restriction of hazardous substances for global market acceptance. The combination of 4" length with 1½" minimum thread length provides optimal unthreaded shank for structural applications requiring precise clamp load distribution.