S-91205A540 1/4"-20 x 3/4" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with Nylon Patch thread locker ensures secure fastening in high-stress environments, maintaining integrity from -70° to 250°F.
• Exceptional tensile strength of 170,000 psi provides reliable performance in heavy-duty applications, reducing the risk of fastener failure.
• Precise Class 3A thread fit offers superior engagement and reduced assembly play, enhancing joint stability in machinery and equipment.
• Durable Black-Oxide finish on Alloy Steel resists corrosion and wear, extending service life in harsh industrial conditions.
• High hardness (Rockwell C37) ensures resistance to deformation under load, supporting repeated use without compromising thread integrity.
• Coarse UNC threads facilitate quick and easy installation, saving time in assembly lines and maintenance tasks.
• Standard hex drive design allows for efficient torque application with common tools, improving installation speed and reducing labor costs.

Professional Applications & Engineering Value

This Socket Head Cap Screw is engineered to address critical challenges in industrial settings, such as vibration-induced loosening and mechanical stress. The Black-Oxide Alloy Steel construction, combined with a Nylon Patch thread locker, provides a robust solution for applications in automotive, aerospace, and heavy machinery, where temperature fluctuations and dynamic loads are common. The UNC coarse thread and Class 3A fit ensure precise alignment and strong clamping force, minimizing the need for re-tightening and reducing downtime. Ideal for use in assembly jigs, engine components, and structural frames, this screw delivers consistent performance under high tensile strength demands, enhancing overall equipment reliability and safety.

Specification Summary & Compliance

This product adheres to ASME B18.3 and ASTM A574 specifications, ensuring dimensional accuracy with a Class 3A thread fit for tight tolerances. It features a 1/4"-20 UNC coarse thread, right-hand direction, and fully threaded design. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards guarantees environmental safety and regulatory adherence for global industrial use.