S-91205A563 1/4"-28 x 3/4" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Permanent vibration resistance with the integrated nylon patch thread locker, ensuring secure fastening in high-stress environments without loosening.
• Exceptional tensile strength of 170,000 psi for reliable performance in heavy-duty industrial applications, reducing the risk of fastener failure.
• High-precision Class 3A fine threads that provide superior fit and resistance to stripping, enhancing assembly efficiency and durability.
• Wide temperature tolerance from -70° to 250°F, making it suitable for extreme operating conditions without compromising locking integrity.
• Corrosion-resistant black-oxide finish on alloy steel for extended service life and protection in harsh environments.
• Rockwell C37 hardness ensures excellent wear resistance and long-term reliability under repetitive loads.
• Full compliance with ASME B18.3, RoHS 3, and REACH standards, guaranteeing safety, environmental responsibility, and interoperability in global markets.

Professional Applications & Engineering Value

This 1/4"-28 UNF socket head cap screw is engineered to address critical challenges in industrial assembly, such as vibration-induced loosening and thermal cycling. The nylon patch thread locker provides a permanent locking mechanism that maintains clamp force in dynamic applications like machinery, automotive systems, and aerospace components. Made from black-oxide alloy steel, it offers superior corrosion resistance and strength, ideal for environments exposed to moisture, chemicals, or high stress. The fine thread design and Class 3A fit ensure precise engagement, reducing the risk of cross-threading and improving load distribution. These features make it a reliable choice for engineers seeking durable, high-performance industrial fasteners that minimize maintenance and downtime.

Specification Summary & Compliance

This screw features a 1/4"-28 UNF fine thread with Class 3A tolerance for high precision, fully threaded design, and a hex drive size of 3/16". It meets ASME B18.3 specifications for dimensional consistency and is manufactured in compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards, ensuring environmental safety and regulatory adherence for global industrial use.