S-91205A554 1/4"-20 x 3" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Superior vibration resistance with integrated nylon patch thread locker that maintains secure fastening from -70°F to 250°F
• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress industrial applications
• Precise Class 3A thread fit provides superior engagement and consistent clamping force in demanding assemblies
• Corrosion-resistant black-oxide finish on alloy steel extends service life in challenging industrial environments
• Optimized socket head design with hex drive allows for high torque application and flush mounting in confined spaces
• Partially threaded shank design enables precise positioning while maximizing grip length for enhanced joint integrity
• Industry compliance assurance with ASME B18.3 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these socket head cap screws combine black-oxide alloy steel construction with advanced locking technology to solve critical fastening challenges. The nylon patch thread locker effectively prevents loosening under vibration and thermal cycling from -70° to 250°F, making them ideal for machinery, automotive assemblies, and equipment subjected to dynamic loads. The UNC coarse thread with Class 3A fit ensures rapid installation and reliable engagement in both soft and hard materials, while the partially threaded design provides optimal stress distribution. With Rockwell C37 hardness and 170,000 psi tensile strength, these fasteners deliver exceptional durability in high-performance applications where failure is not an option.

Specification Summary & Compliance

This 1/4"-20 x 3" socket head cap screw features precision UNC coarse threads with Class 3A fit for superior dimensional accuracy and thread engagement. Manufactured to ASME B18.3 specifications using ASTM A574 alloy steel, the fastener delivers consistent performance across industrial applications. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safe use in regulated industries. The combination of black-oxide surface treatment and nylon patch locking technology provides both corrosion resistance and vibration-resistant fastening capabilities.