S-91259A805 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Durability: Crafted from high-grade alloy steel with a Rockwell C32 hardness, ensuring long-lasting performance in demanding industrial environments.
• Superior Corrosion Resistance: The black oxide finish provides enhanced protection against rust and wear, extending the screw's service life.
• High Load-Bearing Capacity: With a tensile strength of 140,000 psi and a minimum shear strength of 84,000 psi, it reliably handles heavy mechanical stresses.
• Precision Fit and Alignment: Class 3A thread fit and standard shoulder fit ensure accurate, secure fastening with minimal play in assemblies.
• Easy Installation and Grip: Hex drive (5/16") and knurled head allow for straightforward torque application and secure handling during assembly.
• Broad Industrial Compliance: Meets ASME B18.3, ASTM A574, RoHS 3, and REACH standards, guaranteeing quality and safety for various applications.
• Optimized for Coarse Threading: 1/2"-13 UNC coarse thread facilitates quick assembly and disassembly, reducing installation time in high-volume settings.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in industrial machinery, automation, and precision equipment. The black oxide finish not only resists corrosion but also reduces friction, making it ideal for high-movement parts. Its 1/2"-13 UNC coarse thread and Class 3A thread fit ensure reliable engagement in dynamic loads, preventing loosening under vibration. The 2 3/4" shoulder length provides stable alignment for rotating components like bearings and pulleys, minimizing wear and maintenance. By combining high tensile strength (140,000 psi) with a knurled head for secure grip, this screw enhances assembly efficiency and durability in automotive, aerospace, and heavy equipment sectors, where precision and reliability are paramount.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional tolerances, including a Class 3A thread fit for superior accuracy and a shoulder diameter tolerance of -0.004" to -0.002". It conforms to ASME B18.3 and ASTM A574 manufacturing standards, ensuring consistent quality. Additionally, it is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmentally safe and sustainable industrial practices.