S-91257A881 3/4"-16 x 5 1/2" 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 Grade 8 rating and 150,000 psi tensile strength for reliable performance in high-stress applications.
- Superior corrosion resistance from zinc yellow-chromate plating, extending service life in harsh industrial environments.
- Precise thread engagement with UNF fine thread and Class 2A fit, ensuring secure fastening and vibration resistance.
- High durability backed by Rockwell C33 hardness, maintaining structural integrity under repeated loads.
- Easy installation and removal with external hex drive and 1 1/8" head width, compatible with standard tools.
- Optimized thread design with partial threading and 1 3/4" minimum thread length for balanced grip and shear strength.
- Compliance with industry standards including ASME B18.2.1 and SAE J429, guaranteeing interchangeability and safety.
Professional Applications & Engineering Value
This Grade 8 hex head screw is engineered to address critical challenges in heavy machinery, construction, and automotive assemblies where high tensile strength and corrosion resistance are paramount. The steel construction, combined with zinc yellow-chromate plating, provides a robust barrier against rust and chemical exposure, reducing maintenance costs. The 3/4"-16 UNF fine thread offers superior clamping force in partially threaded configurations, minimizing stress concentration and preventing loosening under dynamic loads. Ideal for structural frames, engine components, and industrial equipment, this screw ensures long-term reliability while meeting stringent ASME B18.2.1 specifications for dimensional accuracy.
Specification Summary & Compliance
This screw adheres to Class 2A thread fit tolerances and UNF fine thread standards, ensuring precise alignment. It complies with ASME B18.2.1 and SAE J429 Grade 8 for mechanical properties, and meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) for safe usage.
