S-91205A537 1/4"-20 x 1/2" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with integrated nylon patch thread locker prevents loosening under dynamic loads, ensuring long-term joint integrity in high-stress environments.
• Exceptional tensile strength rated at 170,000 psi provides reliable performance in heavy-duty applications, reducing the risk of fastener failure.
• Corrosion-resistant black-oxide finish on alloy steel enhances durability and offers protection in various industrial conditions.
• Precise Class 3A thread fit ensures smooth installation and secure fastening with minimal risk of cross-threading.
• Wide temperature tolerance from -70° to 250°F maintains performance in extreme thermal environments.
• Standard hex drive design allows for easy installation and removal with common tools, improving assembly efficiency.
• Full threading along the entire length provides consistent clamping force and versatility in adjustment.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address critical challenges in industrial assembly, such as vibration-induced loosening and thermal expansion. The nylon patch thread locker actively resists back-off in machinery, automotive, and aerospace applications where dynamic loads are prevalent. Its UNC coarse thread design facilitates quick installation and reliable grip in materials like steel and aluminum, while the high tensile strength and Rockwell C37 hardness ensure it withstands heavy mechanical stresses without deformation. Ideal for precision equipment, engine components, and structural frameworks, this fastener delivers consistent performance under fluctuating temperatures from -70° to 250°F, making it a dependable choice for engineers seeking durability and compliance in demanding environments.

Specification Summary & Compliance

This socket head cap screw features a 1/4"-20 UNC coarse thread with Class 3A fit for precise engagement and meets ASME B18.3 and ASTM A574 specifications, ensuring dimensional accuracy and manufacturing consistency. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing adherence to environmental and safety standards for industrial use.