S-91259A803 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Durability: Made from high-strength alloy steel with a black oxide finish for superior corrosion resistance, ensuring long-lasting performance in harsh industrial environments.
• Precision Fit & Stability: Class 3A thread fit and controlled shoulder tolerances provide secure, vibration-resistant assembly, reducing maintenance needs and improving machine reliability.
• High Load Capacity: With a tensile strength of 140,000 psi and minimum shear strength of 84,000 psi, this screw handles heavy-duty applications without failure.
• Easy Installation & Removal: The 5/16" hex socket drive and knurled head allow for quick, slip-resistant tightening and adjustment, saving time during assembly.
• Broad Compliance: Meets ASME B18.3 and ASTM A574 standards, and is RoHS 3 and REACH compliant, ensuring safety and regulatory acceptance in global markets.
• Optimized Thread Design: 1/2"-13 UNC coarse threads enable faster engagement and better performance in materials where fine threads may strip.
• Consistent Hardness: Rockwell C32 hardness ensures the screw maintains its shape and strength under repeated stress, extending service life.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address common industrial challenges such as misalignment, high shear loads, and corrosion. The black oxide finish enhances corrosion resistance, making it ideal for machinery, automotive, and aerospace applications where exposure to moisture and chemicals is a concern. The precise shoulder diameter and length tolerances ensure accurate positioning of components like gears and pulleys, reducing wear and improving operational efficiency. With a 1/2"-13 UNC coarse thread and Class 3A fit, it offers reliable fastening in dynamic environments, minimizing loosening from vibrations. Its high tensile and shear strength supports heavy-duty use, while the socket head with knurling allows for easy installation in confined spaces, streamlining maintenance and reducing downtime in production lines.

Specification Summary & Compliance

This shoulder screw features a Class 3A thread fit and adheres to ASME B18.3 and ASTM A574 manufacturing standards for dimensional accuracy. Shoulder diameter tolerance is -0.004" to -0.002", and shoulder length tolerance is -0.005" to 0.005", ensuring precise assembly. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing environmental safety and suitability for industrial applications worldwide.