S-91205A539 1/4"-20 x 5/8" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress industrial applications.
• Permanent Nylon Patch thread locker provides secure, vibration-resistant fastening without requiring additional adhesives.
• Class 3A thread fit delivers superior precision and consistent engagement for reduced assembly issues.
• Black-oxide coating on alloy steel enhances corrosion resistance and durability in demanding environments.
• Wide temperature tolerance from -70° to 250°F maintains locking integrity across extreme operating conditions.
• Hex socket drive design allows for high-torque installation and easy access in confined spaces.
• Full compliance with ASME B18.3 and ASTM A574 guarantees consistent quality and interchangeability.

Professional Applications & Engineering Value

These socket head cap screws are engineered to address critical challenges in machinery, automotive, and heavy equipment assembly. The black-oxide alloy steel construction combined with UNC coarse threads provides excellent shear resistance and fatigue life, preventing loosening under dynamic loads. The integrated nylon patch thread locker eliminates the need for separate locking washers or compounds, streamlining installation while ensuring reliable performance in vibrating environments. Ideal for precision applications requiring Class 3A thread fit, these screws offer consistent clamping force and reduce the risk of cross-threading during high-volume production.

Specification Summary & Compliance

This socket head cap screw features a 1/4"-20 UNC coarse thread with Class 3A fit for precise tolerance, manufactured in accordance with ASME B18.3 and ASTM A574 specifications. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material traceability for global industrial use.