S-91247A603 5/16"-18 x 5" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional strength and durability with Grade 5 steel construction, providing reliable performance under high-stress conditions.
• Superior corrosion resistance from the zinc plating, extending the fastener's lifespan in harsh industrial environments.
• Optimized load distribution and secure fastening due to the coarse UNC thread and Class 2A thread fit, reducing the risk of loosening.
• Easy installation and removal with the external hex drive and hex head design, compatible with standard tools.
• Versatile partial threading (minimum 7/8" thread length) allows for precise clamping force and is ideal for applications requiring unthreaded shank sections.
• High tensile strength of 120,000 psi ensures the screw can withstand significant pulling forces without failure.
• Consistent hardness (Rockwell C25) provides excellent wear resistance and maintains thread integrity during repeated use.

Professional Applications & Engineering Value

This 5/16-18 UNC Grade 5 hex head screw is engineered to address common challenges in industrial assembly and heavy-duty machinery. The partially threaded design, combined with a coarse thread and Class 2A thread fit, ensures secure fastening in materials where vibration resistance is critical, minimizing the risk of joint failure. The zinc plated steel construction offers robust corrosion resistance, making it suitable for outdoor equipment, automotive frames, and structural applications exposed to moisture. Its external hex drive allows for high torque application, facilitating quick installation in confined spaces. By meeting ASME B18.2.1 and SAE J429 standards, this fastener delivers consistent performance, reducing downtime and maintenance costs in demanding engineering environments.

Specification Summary & Compliance

This fastener adheres to precise dimensional standards, including a Class 2A thread fit for consistent assembly and UNC coarse threading with a minimum thread length of 7/8". It complies with ASME B18.2.1 and SAE J429 Grade 5 specifications, ensuring reliability in mechanical properties. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for global industrial use.