S-91205A120 5-40 x 3/8" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Superior vibration resistance with the integrated nylon patch thread locker, ensuring secure fastening in high-stress environments.
• Exceptional tensile strength of 170,000 psi and Rockwell C37 hardness for reliable performance under heavy loads and in demanding applications.
• Wide temperature tolerance from -70° to 250°F, making it suitable for operations in extreme thermal conditions.
• Precise Class 3A thread fit and 5-40 UNC coarse threading for easy installation and robust engagement in various materials.
• Durable black-oxide finish on alloy steel providing enhanced corrosion resistance and a professional appearance.
• Fully threaded design and standard hex drive allow for consistent clamping force and straightforward installation with common tools.
• Compliance with ASME B18.3, RoHS 3, and REACH ensures adherence to industry standards and environmental safety regulations.

Professional Applications & Engineering Value

This socket head cap screw is engineered to address critical challenges in industrial settings, such as maintaining joint integrity under dynamic loads and thermal cycling. The black-oxide alloy steel construction offers excellent durability and resistance to wear, while the nylon patch thread locker prevents loosening caused by vibrations in machinery, automotive assemblies, and precision equipment. With its 5-40 UNC coarse thread and Class 3A fit, it ensures quick, reliable fastening in metals and composites, reducing assembly time and minimizing the risk of thread stripping. Ideal for applications in aerospace, manufacturing, and electronics, this screw provides long-term reliability and performance in environments where temperature fluctuations and high stress are common.

Specification Summary & Compliance

This product features a 5-40 UNC thread with Class 3A precision fit and coarse thread spacing for optimal engagement. It is manufactured in accordance with ASME B18.3 specifications and meets ASTM A574 standards for material quality. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, it ensures environmental safety and is free from hazardous substances, supporting sustainable industrial practices.