S-91286A391 1/2"-20 x 5" 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 demanding industrial applications
- Superior corrosion protection through zinc-flake coating, extending service life in harsh environments
- Reliable thread engagement with Class 2A thread fit ensuring precise assembly and vibration resistance
- High-strength material performance meeting Grade 8 standards with Rockwell C33 hardness for durability
- Optimized torque transmission through external hex drive design for secure installation
- Versatile partial threading allowing both clamping and alignment functions in structural applications
- Regulatory compliance assurance with ASME, SAE, RoHS 3, and REACH standards for global industrial use
Professional Applications & Engineering Value
This Grade 8 hex head screw delivers critical engineering solutions for heavy machinery, structural steel connections, and industrial equipment assembly. The 1/2"-20 UNF fine thread configuration provides superior resistance to vibrational loosening while maintaining high clamping forces. The zinc-flake coated surface treatment offers exceptional corrosion protection in demanding environments, significantly reducing maintenance frequency and replacement costs. With partial threading and minimum 1-1/4" engaged length, this fastener combines the benefits of precise alignment with maximum tensile strength distribution. The external hex drive design ensures reliable torque application during installation, making it ideal for high-stress applications where fastener integrity is paramount to operational safety and equipment longevity.
Specification Summary & Compliance
Manufactured to exacting Class 2A thread fit tolerances with 1/2"-20 UNF threading specification. Complies with ASME B18.2.1 and SAE J429 standards for dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance requirements. The Grade 8 classification ensures consistent performance with 150,000 PSI tensile strength and Rockwell C33 hardness verification.
