S-91211A175 3/8"-16 x 4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Thread-Locking Hex Head Screws
High-Strength Grade 8 Steel Thread-Locking 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
- Superior vibration resistance with nylon patch thread locker that maintains secure fastening from -55° to 250°F
- Exceptional strength for heavy-duty applications with Grade 8 rating and 150,000 psi tensile strength
- Enhanced durability and corrosion protection through zinc yellow-chromate plated steel construction
- Reliable thread engagement with Class 2A fit UNC coarse threads for consistent performance
- Optimized torque transmission through external hex drive design with 9/16" head width
- Versatile partial threading allowing for both clamping and alignment functions in assemblies
- Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for quality assurance
Professional Applications & Engineering Value
Engineered for demanding industrial environments, these Grade 8 hex head screws deliver critical performance where vibration resistance and structural integrity are paramount. The nylon patch thread locker provides permanent vibration resistance without compromising the 150,000 psi tensile strength of the zinc yellow-chromate plated steel construction. The 3/8"-16 UNC coarse thread configuration with partial threading ensures reliable fastening in heavy machinery, construction equipment, and automotive assemblies where thermal cycling from -55° to 250°F would compromise inferior fasteners. This combination of high-strength material and vibration-resistant technology solves common industrial challenges of joint loosening under dynamic loads while maintaining the hardness (Rockwell C33) needed for repeated disassembly and reassembly cycles.
Specification Summary & Compliance
This 4" length hex head screw features 3/8"-16 UNC coarse threads with Class 2A thread fit for precise dimensional accuracy. Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring consistent quality and performance in industrial applications. The fastener maintains Rockwell C33 hardness and meets standard industry requirements for heavy-duty mechanical assemblies, providing reliable performance where high tensile strength and vibration resistance are critical operational parameters.
