S-91205A546 1/4"-20 x 1 1/2" 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 under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Nylon patch thread locker provides secure, vibration-resistant locking from -70° to 250°F, maintaining clamp load without loosening in variable temperature environments.
• Black-oxide finish on alloy steel offers corrosion resistance and a durable, non-galling surface, extending service life in industrial settings.
• Class 3A thread fit delivers precise, tight-tolerance engagement for improved assembly accuracy and reduced cross-threading issues.
• Hex socket drive design allows for high-torque installation with standard tools, enabling efficient assembly in confined spaces.
• Coarse UNC threading facilitates quicker installation and better debris resistance compared to fine threads, speeding up production cycles.
• Partial threading provides an unthreaded shoulder for precise alignment and shear strength, ideal for pivoting or sliding mechanisms.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address common industrial challenges such as vibration-induced loosening and thermal expansion. The nylon patch thread locker embedded in the UNC coarse threads ensures lasting retention in machinery subjected to dynamic loads, from automotive assemblies to heavy equipment. The alloy steel construction with a Rockwell C37 hardness provides superior wear resistance, while the black-oxide surface treatment mitigates rust in humid or outdoor environments. Its 1/4-20 thread size and hex drive make it a versatile choice for precision fastening in aerospace, manufacturing, and robotics, where reliability and compliance with strict standards are critical.

Specification Summary & Compliance

This screw features a 1/4"-20 UNC coarse thread with a Class 3A thread fit for high precision, and a partially threaded design with a minimum thread length of 1 inch. It conforms to ASME B18.3 and ASTM A574 specifications, ensuring consistent manufacturing quality. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety for use in regulated industries without hazardous substances.