S-96909A407 4-40 x 5/16" ASME B18.13 Stainless Steel Pan Head Phillips Screws with Split Lock Washer

Key Features & Benefits at a Glance

• Permanent vibration resistance with integrated 410 stainless steel split lock washer that maintains clamping force under dynamic loads
• Superior corrosion protection through 18-8 stainless steel construction and passivated finish for extended service life in harsh environments
• High-strength performance delivering 80,000 psi tensile strength and Rockwell B85 hardness for demanding industrial applications
• Quick installation with Phillips drive and coarse UNC threading that reduces assembly time and prevents cross-threading
• Reliable locking action through the split lock washer design that prevents loosening without requiring additional components
• Standardized compatibility with ASME B18.13 specifications ensuring interchangeability and consistent performance
• Environmental compliance meeting RoHS 3 and REACH regulations for safe use across global markets

Professional Applications & Engineering Value

These 4-40 UNC coarse thread screws with integrated split lock washers solve critical vibration-induced loosening problems in industrial equipment, electronic enclosures, and machinery assemblies. The 18-8 stainless steel core provides excellent corrosion resistance while the passivated finish enhances surface durability against chemical exposure. The fully threaded design ensures maximum engagement in thin materials, and the Phillips pan head offers streamlined installation without protruding components. Engineering teams specify these fasteners for applications requiring permanent vibration resistance where maintenance access is limited, eliminating the need for separate locking components and reducing assembly complexity while maintaining 80,000 psi tensile strength under continuous operational stress.

Specification Summary & Compliance

Manufactured to ASME B18.13 standards with UNC coarse threading (4-40 size) and Class 2A fit tolerance. The 5/16" length provides optimal engagement depth while the 0.222" OD split lock washer ensures consistent locking performance. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Both screw and washer components feature passivated finish for enhanced corrosion resistance, with the lock washer manufactured from 410 stainless steel for matched material compatibility and performance.