S-91205A578 5/16"-18 x 1/2" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional vibration resistance with integrated nylon patch thread locker, preventing loosening in high-stress applications
• Superior corrosion protection from black-oxide coating on alloy steel, extending service life in harsh environments
• High tensile strength of 170,000 psi ensures reliable performance under extreme mechanical loads
• Precise Class 3A thread fit provides tighter tolerances for secure fastening in critical assemblies
• Wide temperature tolerance from -70° to 250°F maintains integrity across diverse operating conditions
• Optimized hex drive design with 1/4" drive size enables efficient installation and high torque application
• Coarse UNC threading allows for quicker assembly and reduced cross-threading risks

Professional Applications & Engineering Value

Engineered for demanding industrial environments, these black-oxide alloy steel socket head cap screws address critical fastening challenges where vibration resistance and corrosion protection are paramount. The nylon patch thread locking technology effectively counters vibrational loosening in machinery, automotive, and heavy equipment applications, while the Class 3A thread fit ensures precise engagement in high-precision assemblies. The combination of 170,000 psi tensile strength and Rockwell C37 hardness provides exceptional load-bearing capacity for structural components and critical joints. The coarse UNC threading facilitates rapid assembly in production environments, reducing installation time without compromising fastener integrity. These fully threaded socket head screws deliver reliable performance in temperature-sensitive applications from industrial ovens to cryogenic equipment.

Specification Summary & Compliance

Manufactured to exacting standards with Class 3A thread fit precision and UNC coarse thread spacing per ASME specifications. Complies with ASME B18.3 dimensional requirements and ASTM A574 material standards. Meets environmental regulations including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) compliance for restricted substances. Features fully threaded design with right-hand thread direction and standard hex drive socket head configuration for consistent performance across industrial applications.