S-91306A318 4-40 x 1/2" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 120,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Superior corrosion resistance from zinc plating protects against rust and extends service life in various industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, minimizing loosening over time.
• Hex drive design allows for easy installation and high torque application, speeding up assembly processes and improving efficiency.
• Fully threaded construction offers consistent holding power along the entire length, enhancing grip in diverse materials.
• High hardness (Rockwell C39) resists wear and deformation, maintaining integrity through repeated use and harsh conditions.
• Compliance with major standards like ASME B18.3 and ASTM F835 ensures quality and reliability for professional engineering projects.

Professional Applications & Engineering Value

These 4-40 UNC thread screws with a rounded head and zinc-plated alloy steel construction are engineered to address common industrial challenges, such as vibration-induced loosening and environmental corrosion. The coarse thread spacing and Class 3A fit provide excellent grip in softer materials or where quick assembly is needed, reducing installation time and improving joint security. Ideal for applications in machinery, electronics, and automotive sectors, these fully threaded screws ensure uniform stress distribution, preventing premature failure. The hex drive facilitates efficient tightening in confined spaces, making them a versatile choice for maintenance and production lines where durability and compliance with ASME B18.3 are critical.

Specification Summary & Compliance

This product features precise dimensions including a 1/2" length, 0.112" thread diameter, and Class 3A thread fit per UNC standards, ensuring high accuracy for industrial use. It meets ASME B18.3 and ASTM F835 specifications for quality and performance, and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmentally responsible sourcing and safety in manufacturing processes.