S-91286A327 1/2"-13 x 2 1/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with 150,000 psi tensile strength and Grade 8 classification, ensuring reliable performance under extreme mechanical stress.
• Superior corrosion protection from the zinc-flake coating, extending service life in harsh industrial environments and outdoor applications.
• Optimized torque transmission via the external hex drive and 3/4" head width, enabling secure installation with standard tools while resisting stripping.
• Enhanced fatigue resistance due to Rockwell C33 hardness, maintaining structural integrity through repeated vibration and dynamic loads.
• Precise thread engagement with UNC coarse threading and Class 2A fit, facilitating quicker assembly and reducing cross-threading risks.
• Versatile partial threading design providing both gripping strength and alignment flexibility for machinery, structural, and heavy equipment applications.
• Full regulatory compliance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards for global industrial use and supply chain integration.

Professional Applications & Engineering Value

Engineered for demanding industrial environments, these Grade 8 hex head screws combine high-strength steel with a zinc-flake coating to address critical challenges like joint failure under heavy loads and corrosion-induced degradation. The 1/2"-13 UNC coarse thread ensures rapid installation in structural steel, machinery bases, and transportation equipment, while the partial threading design allows unthreaded shank sections to bear shear forces without compromising clamp load. With 150,000 psi tensile strength and hardened Rockwell C33 material, these heavy-duty fasteners maintain bolt preload in vibrating systems, reducing maintenance downtime in construction, manufacturing, and automotive assembly applications where reliability is non-negotiable.

Specification Summary & Compliance

This 2 1/4" length hex head screw features precise Class 2A thread fit with 1/2"-13 UNC coarse threads and a minimum threaded length of 1 1/4". Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications, it guarantees dimensional consistency and mechanical performance. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and unrestricted use in international industrial supply chains.