S-90400A312 4-40 x 7/16" ASME B18.13 Steel Pan Head Phillips Screws with Spring Lock Washer

Key Features & Benefits at a Glance

• Superior vibration resistance through the integrated spring lock washer that maintains clamping force under dynamic loads
• Enhanced corrosion protection with zinc-plated steel construction for extended service life in industrial environments
• High-strength performance with 60,000 psi tensile strength and Rockwell B70 hardness for demanding applications
• Secure fastening engagement with Class 2A thread fit and coarse UNC threads ensuring reliable installation
• Optimized drive efficiency featuring Phillips No. 1 drive and pan head design for controlled torque application
• Full-threaded design providing maximum grip length and uniform stress distribution along the entire 7/16" length
• Regulatory compliance assurance meeting ASME B18.13 specifications and environmental standards

Professional Applications & Engineering Value

These 4-40 UNC zinc-plated steel screws deliver exceptional engineering value in vibration-prone applications where fastener integrity is critical. The pan head design with Phillips drive combines easy installation with reliable torque transfer, while the integrated spring lock washer actively counters loosening caused by machinery vibration and thermal cycling. Manufactured from zinc-plated steel, these fasteners provide essential corrosion resistance for industrial equipment, electronic enclosures, and automotive assemblies. The coarse UNC threading ensures rapid installation and superior holding power in various materials, making them ideal for production environments where speed and reliability are paramount. With full threading along the 7/16" length, these screws distribute clamping forces evenly, preventing stress concentration and material deformation.

Specification Summary & Compliance

This 4-40 UNC screw features precise Class 2A thread fit tolerances and coarse thread spacing for optimal engagement. Manufacturing complies with ASME B18.13 specifications for dimensional accuracy and performance standards. The product meets RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) regulations, ensuring environmental responsibility. The zinc-plated steel construction maintains consistent 60,000 psi tensile strength and Rockwell B70 hardness throughout the fastener system, including the integrated spring lock washer component.