S-91205A535 1/4"-20 x 3/8" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Permanent thread locking with nylon patch ensures vibration resistance and prevents loosening in demanding applications
• Exceptional tensile strength of 170,000 psi provides reliable performance in high-stress industrial environments
• Temperature-resistant locking maintains secure fastening across a wide operating range from -70°F to 250°F
• Precision Class 3A thread fit delivers superior engagement and consistent clamping force in critical assemblies
• Corrosion-resistant black-oxide finish on alloy steel substrate enhances durability in various operating conditions
• Hex socket drive design allows for high torque application and secure installation in confined spaces
• Full threading provides maximum grip length and uniform load distribution along the entire fastener

Professional Applications & Engineering Value

These 1/4-20 UNC socket head cap screws with nylon patch thread locking technology solve critical vibration-induced loosening problems in industrial machinery, automotive assemblies, and precision equipment. The black-oxide alloy steel construction combined with Class 3A thread fit ensures reliable performance in high-vibration environments where fastener integrity is paramount. The hex socket drive enables precise installation torque control while the temperature-resistant nylon patch maintains locking effectiveness across extreme thermal cycles from -70°F to 250°F. These fully threaded cap screws are engineered for applications requiring consistent clamping force and vibration resistance without compromising on strength or durability.

Specification Summary & Compliance

Manufactured to ASME B18.3 standards with ASTM A574 material specifications, these socket head cap screws feature precision Class 3A thread fit with UNC coarse threading for optimal engagement. The fasteners are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring they meet current industry standards for restricted substances. The combination of 170,000 psi tensile strength and Rockwell C37 hardness provides mechanical reliability for demanding industrial applications.