S-91205A721 1/2"-13 x 2 1/4" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, ideal for harsh industrial environments.
• Superior tensile strength of 170,000 psi ensures reliable performance under extreme mechanical loads.
• Precise Class 3A thread fit provides secure, vibration-resistant fastening in critical assemblies.
• Temperature-stable nylon patch thread locker maintains locking integrity from -70° to 250°F.
• High hardness (Rockwell C37) offers excellent wear resistance and durability.
• Partially threaded design allows for optimal grip and alignment in varied applications.
• Standard hex drive compatibility enables quick installation with common tools.

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws are engineered to address common industrial challenges such as vibration loosening and corrosion. The UNC coarse thread and Class 3A fit ensure rapid assembly and high clamping force in heavy machinery, automotive, and construction equipment. The nylon patch thread locker secures fasteners in dynamic environments, while the partially threaded shank provides flexibility for precise joint control. Ideal for applications requiring high tensile strength and compliance with rigorous standards, these screws deliver long-term reliability in demanding conditions.

Specification Summary & Compliance

This product meets ASME B18.3 and ASTM A574 specifications, ensuring dimensional accuracy and material integrity. The Class 3A thread fit guarantees tight tolerances for secure fastening. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming environmental and safety adherence for industrial use.