S-90211A309 3/8"-16 x 4" SAE J429 Left-Hand Threaded High-Strength Steel Hex Head Screws
Left-Hand Threaded High-Strength Steel Hex 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
- Exceptional tensile strength of 150,000 psi ensures reliable performance in high-stress industrial applications
- Superior corrosion resistance with zinc yellow-chromate plating extends service life in harsh environments
- Precision Class 3A thread fit provides secure fastening with minimal vibration loosening in left-hand applications
- Grade 8 certification guarantees consistent quality and meets rigorous SAE J429 specifications
- External hex drive design allows for high-torque installation with standard tools
- Fully threaded 4" length offers maximum engagement and adjustment flexibility
- Rockwell C33 hardness maintains structural integrity under repeated loading conditions
Professional Applications & Engineering Value
Engineered for demanding industrial scenarios where reverse-thread applications prevent unintended loosening from rotational forces, this Grade 8 hex head screw delivers critical reliability. The left-hand UNC coarse threading combined with Class 3A precision ensures secure fastening in machinery, heavy equipment, and automotive systems where standard right-hand threads would compromise safety. The zinc yellow-chromate plating provides superior corrosion protection in exposed environments, while the external hex drive facilitates high-torque installation with common tools. These steel fasteners are specifically designed for applications requiring 150,000 psi tensile strength and verified Rockwell C33 hardness, making them ideal for structural connections, rotating assemblies, and maintenance-critical equipment where failure is not an option.
Specification Summary & Compliance
This 3/8"-16 UNC coarse thread fastener features Class 3A thread fit tolerances for precision engagement and meets SAE J429 specifications for Grade 8 mechanical properties. Manufacturing complies with industry standards for dimensional accuracy, thread form, and material composition. The zinc yellow-chromate plating provides RoHS-compliant corrosion protection while maintaining the screw's mechanical integrity. All specifications including 4" length, 9/16" head width, and 1/4" head height are manufactured to consistent industrial fastener standards.
