S-91257A199 5/8"-18 x 12" 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 and Grade 8 classification for reliable performance in high-stress environments.
- Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh industrial conditions.
- Precise thread engagement with UNF fine threading and Class 2A fit, ensuring secure fastening and vibration resistance.
- Optimized torque application through the external hex drive and hex head design, facilitating easy installation with standard tools.
- Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated mechanical stress.
- Versatile partial threading allowing for adjustable clamping force and compatibility with various nut types.
- Industry-standard compliance with ASME B18.2.1 and SAE J429 specifications, guaranteeing interchangeability and quality assurance.
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, this 5/8"-18 UNF Grade 8 hex head screw addresses critical challenges in machinery assembly, structural framing, and equipment manufacturing. The steel construction with Rockwell C33 hardness resists deformation under extreme loads, while the zinc yellow-chromate plating combats corrosion in outdoor or chemically exposed settings. The partial UNF fine threading ensures maximum grip in tapped holes, reducing the risk of loosening from vibrations—common in automotive, construction, and mining sectors. By meeting ASME B18.2.1 and SAE J429 standards, it delivers consistent performance for high tensile strength requirements, minimizing downtime and maintenance costs.
Specification Summary & Compliance
This hex head screw adheres to precise dimensional tolerances, including a Class 2A thread fit for consistent assembly and UNF fine thread specifications. Manufactured in accordance with ASME B18.2.1 and SAE J429 standards, it ensures reliability in inch system applications. The product complies with industry regulations for material and performance, supporting quality assurance in industrial fastening solutions.
