S-91257A744 1/2"-20 x 2 3/4" 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 reliable performance in high-stress assemblies
- Superior corrosion protection through zinc yellow-chromate plating, extending service life in harsh industrial environments
- Precise thread engagement with Class 2A fit and UNF fine threading, ensuring vibration resistance and secure fastening
- Optimized torque transmission via external hex drive and 3/4" head width, enabling efficient installation with standard tools
- Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated mechanical stress
- Versatile partial threading allowing unthreaded shank sections for precise clamping in structural applications
- Regulatory compliance assurance meeting ASME B18.2.1, RoHS 3, and REACH standards for global industrial use
Professional Applications & Engineering Value
These Grade 8 hex head screws deliver critical engineering solutions where failure isn't an option. The 150,000 psi tensile strength and Rockwell C33 hardness provide unmatched reliability in heavy machinery, structural steel connections, and high-vibration equipment. The zinc yellow-chromate plating creates a protective barrier against corrosion in outdoor or chemically aggressive environments, while the 1/2"-20 UNF fine threads offer superior resistance to loosening under dynamic loads. The partially threaded design ensures optimal load distribution across joint interfaces, making these industrial hex head fasteners ideal for precision assemblies requiring both clamping force and shear strength.
Specification Summary & Compliance
Manufactured to exacting ASME B18.2.1 specifications with SAE J429 Grade 8 certification. Features Class 2A thread fit for consistent engagement and UNF fine threading with 1/2"-20 configuration. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Dimensions include 2 3/4" length with 1 1/4" minimum thread length and standard right-hand threading in inch system measurements.
