S-91286A133 1/4"-20 x 5" 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 for reliable performance in demanding applications
- Superior corrosion resistance through zinc-flake coating, extending service life in harsh industrial environments
- Optimized torque transmission with external hex drive design for secure installation and removal
- Enhanced thread engagement with Class 2A thread fit ensuring precise assembly and vibration resistance
- Reduced cross-threading risk through UNC coarse threading for faster installation in tough materials
- Grade 8 certification guaranteeing consistent mechanical properties and reliability
- Partial threading design providing unthreaded shank section for improved shear strength
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver exceptional performance in construction equipment, machinery assembly, and structural frameworks. The steel construction with Rockwell C33 hardness provides optimal balance between strength and ductility, preventing brittle failure under dynamic loads. The zinc-flake coating offers superior corrosion protection compared to conventional platings, making these 1/4"-20 UNC coarse thread fasteners ideal for outdoor equipment and manufacturing environments. The partially threaded design with 3/4" minimum thread length concentrates clamping force where needed while maintaining shank strength, solving common issues of thread stripping and stress concentration in high-vibration applications.
Specification Summary & Compliance
This 5" hex head screw features precise Class 2A thread fit with 1/4"-20 UNC coarse thread specifications, manufactured to ASME B18.2.1 and SAE J429 Grade 8 standards. The fastener maintains full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for global industrial markets and restricted substance-free operation in sensitive applications.
