S-91257A721 1/2"-13 x 2 1/4" 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 tensile strength of 150,000 psi ensures reliable performance in high-stress industrial and construction applications, reducing the risk of fastener failure.
- Superior corrosion resistance from zinc yellow-chromate plating extends service life in harsh environments, minimizing maintenance and replacement costs.
- High hardness rating (Rockwell C33) provides excellent wear resistance and durability, ideal for heavy-duty machinery and equipment.
- Coarse UNC threading with Class 2A fit allows for quick, easy installation and secure fastening, reducing assembly time and improving efficiency.
- External hex drive design offers straightforward tool engagement and high torque capability, facilitating secure tightening in confined spaces.
- Partial threading provides unthreaded shank strength where needed, enhancing grip and stability in dynamic load conditions.
- Compliance with major standards including ASME B18.2.1 and SAE J429 ensures consistent quality and interoperability in professional applications.
Professional Applications & Engineering Value
Engineered for demanding environments, this Grade 8 hex head screw combines high-strength steel and a zinc yellow-chromate finish to address common industrial challenges like vibration loosening and corrosion. The 1/2"-13 UNC coarse thread and Class 2A thread fit ensure precise engagement and resistance to stripping, making it ideal for heavy machinery, structural frameworks, and automotive assemblies. Its partial threading design maximizes clamp load distribution, reducing stress concentration points. By meeting rigorous standards, this screw delivers reliable performance in construction, manufacturing, and equipment maintenance, where failure is not an option.
Specification Summary & Compliance
This screw adheres to Class 2A thread fit tolerances and UNC coarse thread standards, ensuring dimensional accuracy and compatibility. It complies with ASME B18.2.1 and SAE J429 specifications for consistent manufacturing quality. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, supporting environmental and safety regulations in global supply chains.
