S-91259A710 3/8"-16 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Load-Bearing Capacity: With a tensile strength of 140,000 psi and shear strength of 84,000 psi, this shoulder screw ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Superior Corrosion Resistance: The black oxide finish provides enhanced protection against rust and wear, extending the screw's service life in harsh industrial environments and minimizing maintenance needs.
• Precision Thread Fit for Secure Fastening: Class 3A thread fit offers tighter tolerances, ensuring smooth assembly, reduced vibration loosening, and improved joint integrity in mechanical systems.
• Optimized Shoulder Design for Accurate Alignment: The 1/2" shoulder diameter with controlled tolerances allows for precise component positioning, reducing misalignment and wear in pivoting or rotating assemblies.
• Easy Installation and Removal: The 1/4" hex socket drive and knurled head provide excellent grip and torque application, speeding up assembly and disassembly while reducing tool slippage.
• High Durability and Material Strength: Made from alloy steel with Rockwell C32 hardness, this screw maintains its structural integrity under repeated loads, ideal for heavy-duty and high-cycle applications.
• Compliance with Industry Standards: Meets ASME B18.3 specifications, ensuring consistent quality, interchangeability, and reliability in professional engineering projects.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in industrial and mechanical systems, where precision, strength, and durability are paramount. The 3/8"-16 UNC coarse thread with Class 3A fit ensures secure fastening in high-vibration environments, preventing loosening in machinery, automotive assemblies, and robotics. The black oxide finish enhances corrosion resistance, making it suitable for applications exposed to moisture or chemicals, such as in manufacturing equipment or outdoor machinery. The precisely machined shoulder diameter and length provide stable bearing surfaces for rotating parts, reducing friction and wear in pivots, linkages, and guide mechanisms. By combining high tensile strength with compliance to ASME B18.3, this screw delivers reliable performance in demanding sectors like aerospace, automation, and heavy equipment, where fastener failure can lead to costly downtime.

Specification Summary & Compliance

This shoulder screw features a 3/8"-16 UNC thread with Class 3A fit for precise thread engagement, and a shoulder diameter tolerance of -0.004" to -0.002" for accurate alignment. It complies with ASME B18.3 manufacturing standards, ensuring dimensional consistency and performance reliability. Additionally, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, supporting safe and sustainable use in global industrial applications.