S-91309A552 1/4"-20 x 2 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 that protects against rust in demanding industrial environments
- Exceptional tensile strength of 60,000 PSI ensures reliable performance under high-stress applications
- Rockwell B69 hardness provides excellent durability and resistance to wear and deformation
- Class 2A thread fit with UNC coarse threading offers easier assembly and reduced risk of cross-threading
- Fully threaded design delivers maximum grip and holding power across the entire 2 1/2" length
- External hex drive with standard 7/16" head width allows for high-torque installation using common tools
- Compliance with major industry standards including ASME B18.2.1 and ASTM A307 for guaranteed quality and reliability
Professional Applications & Engineering Value
These 1/4"-20 UNC hex head screws are engineered to solve critical fastening challenges in industrial settings where vibration resistance and long-term reliability are paramount. The steel construction with zinc plating provides essential corrosion protection for outdoor equipment, machinery, and structural applications exposed to harsh conditions. The coarse UNC threading ensures secure fastening in softer materials and prevents loosening under dynamic loads. With full threading along the 2 1/2" length, these screws distribute clamping force evenly, making them ideal for heavy-duty assemblies requiring maximum holding power. The external hex drive design facilitates quick installation and removal while accommodating high torque requirements in manufacturing, construction, and maintenance operations.
Specification Summary & Compliance
This hex head screw features precise Class 2A thread fit tolerance for consistent performance and meets ASME B18.2.1 dimensional specifications under ASTM A307 grade standards. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across various industrial applications while maintaining 60,000 PSI tensile strength and Rockwell B69 hardness specifications.
