S-91257A551 1/4"-20 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 load-bearing capacity with 150,000 psi tensile strength, ensuring reliable performance in high-stress applications.
- Superior corrosion resistance from zinc yellow-chromate plating, extending service life in harsh industrial environments.
- High hardness rating of Rockwell C33 for excellent wear resistance and reduced risk of stripping or deformation.
- Coarse UNC threading provides faster installation and better grip in a variety of materials, reducing assembly time.
- Partial threading design allows for precise clamping force control, minimizing the risk of joint loosening under vibration.
- Class 2A thread fit ensures consistent, reliable engagement with nuts and tapped holes, improving assembly efficiency.
- External hex drive and hex head offer easy installation with standard tools, even in confined spaces.
Professional Applications & Engineering Value
Engineered for demanding environments, this Grade 8 hex head screw delivers robust performance in heavy machinery, construction, and automotive assemblies. The steel material combined with zinc yellow-chromate plating effectively combats rust and corrosion, addressing common failure points in outdoor or high-moisture settings. Its 1/4"-20 UNC coarse thread and partial threading enhance grip and distribute stress evenly, reducing the likelihood of fatigue under dynamic loads. Ideal for structural frameworks and equipment requiring 150,000 psi tensile strength, this fastener ensures long-term reliability, minimizing maintenance downtime and replacement costs in industrial applications.
Specification Summary & Compliance
This screw adheres to Class 2A thread fit and UNC coarse thread standards, ensuring precise dimensional accuracy. It meets ASME B18.2.1 and SAE J429 specifications for Grade 8 fasteners, with full compliance to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, guaranteeing safety and sustainability in industrial use.
