S-91236A556 1/4"-20 x 3 1/2" ASME B18.2.1, ASTM A307 Low-Strength Steel Hex Head Screws
Low-Strength 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
- Superior corrosion resistance with zinc plating for extended service life in demanding environments
- High tensile strength of 60,000 psi ensures reliable performance under heavy loads and vibration
- Rockwell B69 hardness provides excellent durability and resistance to wear and deformation
- Class 2A thread fit offers optimal assembly clearance for efficient installation while maintaining secure fastening
- External hex drive design enables high-torque applications with standard tools for quick maintenance
- Partial threading configuration allows for precise clamping force distribution in structural applications
- Coarse UNC thread pattern facilitates rapid installation and reduced cross-threading risks in industrial settings
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, these steel hex head screws deliver exceptional mechanical performance where vibration resistance and structural integrity are critical. The 1/4"-20 UNC coarse thread design provides superior engagement in various materials while the zinc plating surface treatment effectively combats corrosion in harsh operating environments. The partially threaded configuration ensures optimal stress distribution, making these fasteners ideal for construction assemblies, machinery frames, and equipment mounting where precise clamping force is required. With their external hex drive compatibility, they enable high-torque installation using standard tools, significantly reducing assembly time in manufacturing and maintenance operations.
Specification Summary & Compliance
Manufactured to exacting ASME B18.2.1 dimensional standards with Class 2A thread fit tolerances for consistent performance. The UNC coarse thread (1/4"-20) ensures reliable engagement across various applications. These steel hex head screws comply with ASTM A307 material specifications and meet critical regulatory requirements including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards for industrial use.
