S-91247A605 5/16"-18 x 5 1/2" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 120,000 psi ensures reliable performance under heavy loads, reducing the risk of fastener failure in demanding applications.
• Corrosion-resistant zinc plating provides a durable protective layer, extending service life in various industrial environments and reducing maintenance needs.
• Grade 5 steel construction with Rockwell C25 hardness offers an optimal balance of strength and toughness, resisting wear and deformation during installation and use.
• Coarse UNC threads and Class 2A thread fit enable quick, easy assembly and secure fastening, even in materials where fine threads might strip or fail.
• Partially threaded design with 7/8" minimum thread length allows for precise clamping force control and is ideal for applications requiring unthreaded shank sections.
• External hex drive and standard hex head facilitate straightforward installation with common tools, improving efficiency in assembly and maintenance operations.
• Compliance with ASME B18.2.1 and SAE J429 standards guarantees consistent quality, dimensional accuracy, and interoperability with other standardized components.

Professional Applications & Engineering Value

This Grade 5 hex head screw is engineered to address critical fastening challenges in heavy machinery, construction, and automotive assemblies. The zinc plated steel construction combats corrosion, making it suitable for outdoor or humid conditions where rust can compromise integrity. Its 5/16"-18 UNC coarse thread and Class 2A thread fit ensure rapid, secure engagement in coarse-grained materials, reducing installation time and preventing cross-threading. The partial threading design provides an unthreaded shank that resists shear forces, ideal for structural joints requiring precise clamp load distribution. With a tensile strength of 120,000 psi and Rockwell C25 hardness, it withstands high-stress environments, offering engineers a dependable solution for applications demanding durability, compliance with ASME B18.2.1, and adherence to environmental regulations like RoHS and REACH.

Specification Summary & Compliance

This fastener adheres to Class 2A thread fit tolerances per UNC standards, ensuring precise dimensional accuracy and compatibility. It meets ASME B18.2.1 and SAE J429 specifications for manufacturing consistency and performance. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, confirming the absence of hazardous substances and supporting sustainable industrial practices.