S-91257A143 3/8"-24 x 4 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
- Maximum load-bearing capacity with Grade 8 steel construction, delivering 150,000 psi tensile strength for demanding industrial applications.
- Superior corrosion resistance through zinc yellow-chromate plating, extending service life in harsh or outdoor environments.
- Precise thread engagement with Class 2A UNF fine threads, ensuring reliable, vibration-resistant connections in machinery and equipment.
- High hardness rating of Rockwell C33, providing excellent wear resistance and durability under repetitive stress.
- Optimized for heavy torque applications with an external hex drive and 9/16" head width, allowing secure installation with standard tools.
- Versatile partial threading design, enabling effective clamping where unthreaded shank sections add shear strength.
- Compliance with ASME B18.2.1 and SAE J429 standards, guaranteeing consistent quality and interchangeability in professional settings.
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, this Grade 8 hex head screw addresses critical challenges in machinery assembly, structural frameworks, and automotive systems. The 3/8"-24 UNF fine thread configuration enhances fatigue resistance and minimizes loosening under dynamic loads, while the zinc yellow-chromate plating provides a robust barrier against rust and chemical exposure. With a partially threaded shank, it offers superior clamping force and shear resistance in bolted joints, making it ideal for construction equipment, agricultural machinery, and high-stress automotive components. Its compliance with ASME B18.2.1 ensures dimensional accuracy and reliability, reducing downtime and maintenance costs in B2B procurement scenarios.
Specification Summary & Compliance
This fastener features a Class 2A thread fit for consistent engagement, UNF fine threading with 24 TPI, and a 4 3/4" length including a 1" minimum thread length. It conforms to ASME B18.2.1 and SAE J429 specifications, with material and manufacturing processes aligned to industrial standards. The zinc yellow-chromate finish meets RoHS and REACH environmental compliance, ensuring safe use in global markets.
