S-91257A424 1/4"-28 x 6 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws
High-Strength Grade 8 Steel Hex Head Screws
Image may differ from product. See technical specification for details.
Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
- Fast delivery
- Enjoy discounts on bulk purchases
- Secure Payment
- Fast Global Shipping
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.
- Superior corrosion resistance from zinc yellow-chromate plating extends service life in harsh industrial environments.
- High hardness rating (Rockwell C33) provides excellent wear resistance and maintains thread integrity under heavy loads.
- Precision UNF fine threading offers superior vibration resistance and secure fastening in critical assemblies.
- Partially threaded design allows for optimal clamping force distribution and easier alignment in structural applications.
- External hex drive compatibility enables high-torque installation with standard tools, improving assembly efficiency.
- Industry standard compliance (ASME B18.2.1/SAE J429) guarantees dimensional accuracy and interchangeability across systems.
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, this Grade 8 hex head screw addresses critical challenges in machinery assembly, structural framing, and equipment manufacturing. The steel construction with UNF fine thread profile maintains clamping force under extreme vibration, while the zinc yellow-chromate plating provides essential corrosion protection in demanding environments. The partially threaded design concentrates strength where needed most, preventing stress concentration at the thread run-out. With 150,000 psi tensile strength and Rockwell C33 hardness, this fastener delivers reliable performance in construction, automotive, and manufacturing sectors where failure is not an option.
Specification Summary & Compliance
This 1/4"-28 hex head screw features Class 2A thread fit for standard industrial applications, ensuring proper clearance and assembly compatibility. Manufacturing complies with ASME B18.2.1 and SAE J429 standards for dimensional accuracy and mechanical properties. The 6 1/2" length with 1" minimum thread length provides versatile fastening solutions. The zinc yellow-chromate finish meets industry requirements for corrosion protection, while the Grade 8 classification guarantees consistent high-strength performance across production batches.
