S-91259A438 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Durability: Crafted from high-strength alloy steel with a black oxide finish to resist corrosion and extend service life in demanding industrial environments.
• Superior Load-Bearing Capacity: With a tensile strength of 140,000 psi and a minimum shear strength of 84,000 psi, this screw reliably handles high-stress applications without failure.
• Precision Thread Fit: Class 3A UNC coarse threads ensure a secure, vibration-resistant connection, reducing the risk of loosening in machinery and assemblies.
• Enhanced Grip and Alignment: The knurled head texture and standard shoulder fit provide improved handling and stable positioning during installation and operation.
• Wide Regulatory Compliance: Meets ASME B18.3, RoHS 3, and REACH standards, ensuring safety, environmental responsibility, and global acceptance for your projects.
• Optimized for Heavy-Duty Use: Rockwell C32 hardness and a robust socket head design withstand repeated torque and mechanical stress, ideal for precision engineering applications.
• Easy Installation and Maintenance: Hex drive style and standard socket head profile allow for quick, tool-friendly assembly, saving time in production and maintenance cycles.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in industrial settings, such as misalignment and component wear. The black oxide finish not only enhances corrosion resistance but also reduces friction, making it suitable for high-motion assemblies like pivots, gears, and linkages. With a 1/2"-13 UNC coarse thread and Class 3A fit, it ensures rapid installation and reliable performance in vibrating machinery, automotive systems, and heavy equipment. The precise shoulder diameter and length provide consistent spacing and alignment, minimizing downtime and maintenance costs. Ideal for applications requiring high tensile and shear strength, this screw supports robust engineering solutions while complying with industry standards for safety and sustainability.

Specification Summary & Compliance

This shoulder screw features a 1/2"-13 UNC thread with Class 3A precision fit and a shoulder diameter tolerance of -0.004" to -0.002" for exact alignment. It adheres to ASME B18.3 manufacturing specifications and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material integrity. The alloy steel construction meets ASTM A574 standards, providing consistent performance in demanding industrial applications.