S-91772A555 1/4"-28 x 3/8" ASME B18.6.3 Stainless Steel Pan Head Phillips Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with passivated 18-8 stainless steel construction, ensuring long-term reliability in harsh industrial environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B70 hardness, providing reliable performance under high-stress conditions
• Precision fine threading with Class 2A UNF threads offering superior vibration resistance and secure fastening in critical applications
• Optimized drive efficiency with Phillips No. 3 drive design for easy installation and reduced cam-out during assembly operations
• Enhanced durability through fully threaded construction and rounded pan head profile, distributing stress evenly and preventing head stripping
• Regulatory compliance assurance meeting ASME B18.6.3 specifications while being RoHS 3 and REACH compliant for global market acceptance
• Versatile industrial application with standard 3/8" length and fine thread spacing suitable for precision equipment and machinery assembly

Professional Applications & Engineering Value

These 1/4"-28 UNF pan head screws deliver exceptional engineering value through their passivated 18-8 stainless steel composition, specifically engineered to combat corrosion in demanding industrial settings. The fine thread configuration with Class 2A tolerance ensures superior vibration resistance, making them ideal for precision machinery, electronic enclosures, and automotive components where loosening under dynamic loads is a critical concern. The combination of 70,000 psi tensile strength and Rockwell B70 hardness provides reliable performance in high-stress applications while maintaining ductility. The Phillips No. 3 drive system offers efficient installation with reduced tool slippage, significantly improving assembly line productivity. These fully threaded screws with their rounded pan head design distribute clamping forces evenly, preventing stress concentration and material deformation in sensitive applications.

Specification Summary & Compliance

Manufactured to exacting ASME B18.6.3 specifications, these screws feature precision Class 2A thread fit with UNF fine threading (1/4"-28) ensuring consistent engagement and reliable performance. The 3/8" length and 0.25" thread diameter maintain strict dimensional accuracy for uniform application across industrial assemblies. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations ensures environmental safety and global market acceptance, while the passivated surface treatment enhances corrosion resistance without compromising material integrity.