S-91205A675 1/4"-20 x 2 1/4" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Secure vibration-resistant fastening with integrated nylon patch thread locker that maintains integrity across temperatures from -70°F to 250°F
• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress industrial applications
• Precise Class 3A thread fit provides superior engagement and reduces the risk of cross-threading during assembly
• Durable black-oxide alloy steel construction offers enhanced corrosion resistance and extended service life in demanding environments
• Hex socket drive design allows for high-torque installation in confined spaces with standard tools
• Partially threaded shank enables optimal clamping force distribution and precise joint positioning
• Industry-standard compliance with ASME B18.3 specifications ensures consistent quality and interchangeability

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw delivers critical engineering solutions where vibration resistance and structural integrity are paramount. The nylon patch thread locker embedded in the UNC coarse threads prevents loosening under dynamic loads, making it ideal for machinery, automotive assemblies, and heavy equipment subjected to constant stress cycles. The Rockwell C37 hardness rating combined with the 170,000 psi tensile strength ensures these fasteners maintain clamp load in high-vibration environments where inferior screws would fail. The partially threaded design provides unthreaded shank sections for superior shear strength, while the hex socket drive enables flush installation in recessed applications. These industrial-grade fasteners meet rigorous performance requirements for manufacturing, aerospace, and precision equipment applications.

Specification Summary & Compliance

This socket head cap screw features 1/4"-20 UNC Class 3A threads with coarse spacing and partial threading over a 1" minimum length. Manufactured to ASME B18.3 specifications using ASTM A574 alloy steel with black-oxide surface treatment. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial markets.