S-91286A381 1/2"-20 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 load-bearing capacity with 150,000 psi tensile strength for critical structural applications
- Superior corrosion resistance provided by zinc-flake coating in harsh industrial environments
- Precise thread engagement with Class 2A UNF fine threads ensuring reliable fastening performance
- Optimized torque transmission through external hex drive design for efficient installation
- Enhanced durability with Rockwell C33 hardness maintaining structural integrity under stress
- Versatile partial threading allowing both clamping and alignment functions in assemblies
- Regulatory compliance assurance meeting ASME B18.2.1, RoHS 3, and REACH standards
Professional Applications & Engineering Value
This Grade 8 hex head screw delivers exceptional engineering value for heavy-duty industrial applications where failure is not an option. The 1/2"-20 UNF fine thread configuration provides superior resistance to vibration loosening compared to coarse threads, while the partial threading design offers optimal clamp load distribution. The zinc-flake coating creates a robust barrier against corrosion in demanding environments, from manufacturing equipment to structural frameworks. With 150,000 psi tensile strength and Rockwell C33 hardness, this fastener maintains integrity under extreme mechanical stress, making it ideal for critical assemblies in construction machinery, heavy vehicle manufacturing, and industrial processing equipment where reliability and longevity are paramount.
Specification Summary & Compliance
Manufactured to precise Class 2A thread fit tolerances with 1/2"-20 UNF fine threads and 3" length. Complies with ASME B18.2.1 specifications where identified with SAE J429 Grade 8 requirements. Meets environmental standards including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) regulations as of June 2022. Features external hex drive with 3/4" head width and 5/16" head height for standard tool compatibility.
