S-91205A550 1/4"-20 x 2" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws
Alloy Steel Thread-Locking Socket Head Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Secure vibration resistance with the integrated Nylon Patch thread locker, maintaining hold from -70° to 250°F.
- Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress industrial loads.
- Superior wear and corrosion resistance from the Black-Oxide Alloy Steel material and Rockwell C37 hardness.
- Precise, reliable engagement with Class 3A UNC coarse threads for easy assembly and strong hold.
- Optimized for high-torque applications using a standard 3/16" hex drive socket head for secure, slip-free installation.
- Versatile partial threading allows for precise clamping control in a wide range of assembly configurations.
- Guaranteed dimensional consistency and interchangeability, manufactured to meet ASME B18.3 specifications.
Professional Applications & Engineering Value
This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address critical challenges in machinery, automotive, and heavy equipment assembly. Its high tensile strength and Rockwell C37 hardness provide durability against dynamic loads and fatigue, while the Nylon Patch thread locker effectively prevents loosening from vibration—common in motors and moving parts. The UNC coarse thread and Class 3A fit ensure quick, accurate installation with reduced cross-threading risk. The partially threaded design offers flexibility for applications requiring unthreaded shank strength, making it ideal for precision fixturing, engine components, and structural frames where reliability and compliance with industrial standards are paramount.
Specification Summary & Compliance
This screw adheres to ASME B18.3 dimensional standards and ASTM A574 material specifications, ensuring precise thread geometry with a Class 3A thread fit for superior engagement. It features a 1/4"-20 UNC coarse thread, 2" length with a 1" minimum thread length, and a 3/16" hex drive. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for use in environmentally conscious and global industrial markets.
