S-91205A531 1/4"-20 x 1/4" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking: Nylon patch thread locker ensures secure fastening in high-vibration environments, maintaining integrity from -70° to 250°F.
• Exceptional strength and durability: Made from black-oxide alloy steel with 170,000 psi tensile strength and Rockwell C37 hardness for reliable performance under heavy loads.
• Precise thread fit: Class 3A UNC coarse threads provide superior engagement and reduce the risk of cross-threading in industrial assemblies.
• Corrosion protection: Black-oxide coating enhances resistance to rust and wear, extending service life in harsh conditions.
• Easy installation and removal: Standard hex socket head with 3/16" drive allows for efficient torque application using common tools.
• Full threading for versatile use: Fully threaded design ensures consistent clamping force across the entire length, ideal for various mounting applications.
• Compliance with industry standards: Meets ASME B18.3 and ASTM A574 specifications, guaranteeing quality and interoperability in professional settings.

Professional Applications & Engineering Value

This 1/4"-20 UNC socket head cap screw is engineered to address critical challenges in industrial fastening, such as loosening under vibration and corrosion in demanding environments. The black-oxide alloy steel construction, combined with a nylon patch thread locker, provides a robust solution that maintains clamp load integrity from -70° to 250°F, making it ideal for machinery, automotive, and aerospace applications. Its coarse UNC threads and Class 3A fit ensure quick, reliable assembly with reduced risk of stripping, while the hex drive design facilitates easy access in confined spaces. By offering high tensile strength and vibration resistance, this screw minimizes maintenance downtime and enhances the longevity of assembled components, delivering consistent performance in industrial socket screw applications.

Specification Summary & Compliance

This product features precise Class 3A thread fit with UNC coarse threads and a diameter of 0.25", ensuring accurate engagement. It complies with ASME B18.3 and ASTM A574 manufacturing standards, and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming its suitability for global industrial use without hazardous substances.