S-91257A571 1/4"-28 x 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 tensile strength of 150,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
- Rockwell C33 hardness rating provides superior resistance to wear and deformation, extending the fastener's service life.
- Zinc yellow-chromate plating offers excellent corrosion resistance, making it ideal for harsh industrial environments.
- Class 2A thread fit guarantees precise, easy assembly and consistent engagement with nuts and tapped holes.
- Partially threaded design with 1/4"-28 UNF fine threads allows for secure clamping in materials where full threading isn't necessary, improving versatility.
- External hex drive and hex head facilitate straightforward installation and removal with common tools, saving time on the job site.
- Compliance with ASME B18.2.1 and SAE J429 standards ensures consistent quality and interoperability in mechanical assemblies.
Professional Applications & Engineering Value
This Grade 8 hex head screw is engineered to address critical challenges in heavy-duty industrial settings, such as machinery assembly, construction equipment, and automotive systems. The steel material combined with a zinc yellow-chromate finish provides robust protection against rust and chemical exposure, which is essential for outdoor or corrosive environments. With a 1/4"-28 UNF fine thread and partial threading, it delivers optimal grip and vibration resistance in applications where precise tension control is needed. The external hex drive allows for high-torque installation, ensuring secure fastening in high-load scenarios, while the 4" length accommodates thick materials without compromising structural integrity.
Specification Summary & Compliance
This fastener adheres to precise dimensional standards, including Class 2A thread fit for consistent accuracy and UNF fine threads with a size of 1/4"-28. It meets ASME B18.2.1 and SAE J429 specifications for mechanical properties and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material restrictions are upheld.
