S-91257A544 1/4"-20 x 1 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 capability with 150,000 psi tensile strength for reliable performance in high-stress applications
- Superior corrosion protection through zinc yellow-chromate plating that extends service life in harsh environments
- Optimized torque transmission with external hex drive design ensuring secure installation and removal
- Enhanced thread engagement with UNC coarse threading that resists vibration loosening and simplifies alignment
- Precision manufacturing to Class 2A thread fit standards for consistent performance and compatibility
- Grade 8 certification guaranteeing Rockwell C33 hardness for maximum durability and wear resistance
- Versatile partial threading design providing both gripping strength and clearance where needed
Professional Applications & Engineering Value
Engineered for demanding industrial applications, these Grade 8 hex head screws deliver exceptional reliability in machinery assembly, structural frameworks, and heavy equipment manufacturing. The zinc yellow-chromate plating provides superior corrosion resistance, significantly extending service life in environments exposed to moisture, chemicals, and outdoor elements. The 1/4"-20 UNC coarse threading ensures rapid installation and maintains secure fastening under vibration, while the external hex drive allows for high torque application without stripping. With 150,000 psi tensile strength and Rockwell C33 hardness, these fasteners prevent failure in critical joints, reducing maintenance downtime and replacement costs across automotive, construction, and industrial manufacturing sectors.
Specification Summary & Compliance
Manufactured to precise Class 2A thread fit tolerances with 1/4"-20 UNC coarse threading and 1 1/4" length. Complies with ASME B18.2.1 and SAE J429 Grade 8 specifications for dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance requirements for environmental safety and restricted substance control.
