S-91286A171 5/16"-18 x 3" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws
High-Strength Grade 8 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 provided by zinc-flake coating extends service life in harsh environments
- Rockwell C33 hardness rating maintains structural integrity under heavy loads and repeated use
- Partially threaded UNC coarse design allows for optimal clamping force and faster installation
- External hex drive configuration enables high-torque application with standard tools
- Grade 8 classification guarantees consistent quality for critical fastening requirements
- Precision Class 2A thread fit ensures smooth assembly and reliable engagement
Professional Applications & Engineering Value
Engineered for demanding industrial applications, these Grade 8 hex head screws provide exceptional reliability in construction, heavy machinery, and structural assemblies. The zinc-flake coated finish offers superior protection against corrosion, making them ideal for outdoor equipment and harsh environmental conditions. The 5/16"-18 UNC coarse thread design ensures rapid installation while maintaining secure fastening in vibration-prone applications. With partial threading and external hex drive, these screws deliver optimal clamping force and accommodate high-torque installation, reducing assembly time while providing maximum durability in critical joints and structural connections.
Specification Summary & Compliance
Manufactured to exacting standards with Class 2A thread fit and UNC coarse thread specifications. Complies with ASME B18.2.1 and SAE J429 manufacturing standards, ensuring dimensional accuracy and performance consistency. Meets environmental regulations including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) requirements for safe industrial use. The Grade 8 classification verifies mechanical properties including tensile strength, hardness, and material quality for reliable performance in critical applications.
