S-91257A991 1"-14 x 6" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance under extreme loads and vibrations in heavy machinery and structural applications.
• Superior corrosion resistance from Zinc Yellow-Chromate plating protects against rust and environmental degradation, extending service life in harsh industrial conditions.
• Precise Class 2A thread fit with extra fine threading provides secure, vibration-resistant connections and improved fatigue resistance in high-stress assemblies.
• Grade 8 material hardness (Rockwell C33) offers excellent wear resistance and durability, reducing fastener failure in demanding engineering applications.
• External hex drive design allows for high-torque installation with standard tools, ensuring tight, secure fastening in confined spaces.
• Partial threading combines strong grip with unthreaded shank strength, ideal for applications requiring clamping force without thread engagement.
• Full compliance with ASME B18.2.1 and SAE J429 standards guarantees dimensional accuracy and interchangeability for reliable industrial use.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, this Grade 8 hex head screw addresses critical challenges in machinery assembly, construction, and automotive sectors where vibration loosening and material fatigue are common. The 1"-14 extra fine thread design enhances load distribution and resistance to dynamic stresses, while the Zinc Yellow-Chromate plating provides a robust barrier against corrosive environments, reducing maintenance costs. Its partially threaded configuration ensures optimal clamping force in bolted joints, making it ideal for structural steel connections, engine components, and high-pressure equipment that demand both high tensile strength and long-term reliability under cyclic loading conditions.

Specification Summary & Compliance

This fastener meets Class 2A thread fit tolerances per UNS standards with a 1"-14 extra fine thread and 6" length. Manufacturing conforms to ASME B18.2.1 and SAE J429 specifications for dimensional consistency. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material restrictions adherence.