S-95345A428 4-40 x 5/16" ASME B18.13 Stainless Steel Pan Head Phillips Screws with External-Tooth Lock Washer

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments.
• Reliable vibration resistance thanks to the integrated external-tooth lock washer made from 410 stainless steel, preventing loosening under dynamic loads.
• High tensile strength of 70,000 psi ensures durable fastening for demanding applications without failure.
• Easy installation and removal with No. 1 Phillips drive and fully threaded 4-40 UNC coarse spacing for quick, secure engagement.
• Precise thread fit (Class 2A) provides consistent performance and reduces the risk of cross-threading in assembly.
• Comprehensive compliance with ASME B18.13 standards, RoHS 3, and REACH, ensuring safety and environmental responsibility.
• Versatile pan head design offers a low-profile, rounded head for flush mounting and enhanced aesthetic in finished products.

Professional Applications & Engineering Value

These 4-40 UNC rounded head Phillips screws with external-tooth lock washers are engineered to address common industrial challenges like vibration-induced loosening and corrosion in machinery, electronics, and automotive assemblies. The 18-8 stainless steel material combined with a passivated finish delivers exceptional resistance to moisture and chemicals, extending service life in demanding environments. The coarse thread spacing and fully threaded design ensure rapid, reliable fastening, while the integrated lock washer maintains clamp force under stress. Ideal for applications requiring secure, reusable fasteners that meet rigorous ASME B18.13 specifications, these screws reduce maintenance needs and enhance operational reliability in B2B settings.

Specification Summary & Compliance

This screw features precise Class 2A thread fit and UNC coarse threading for consistent performance. It complies with ASME B18.13 manufacturing standards and adheres to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material quality. Dimensions include a 5/16" length, 0.219" head diameter, and 0.23" washer OD, with all components meeting specified tolerances for reliable industrial use.