S-91259A903 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior torque transmission with 5/16" hex drive and knurled head for secure tool engagement and reduced slipping during installation
• Exceptional load-bearing capacity from alloy steel construction, offering 140,000 psi tensile strength and 84,000 psi shear strength for heavy-duty applications
• Enhanced corrosion resistance with black oxide finish, providing durable protection in demanding industrial environments
• Precise thread engagement with Class 3A thread fit and 1/2"-13 UNC coarse threads for reliable fastening and vibration resistance
• Accurate shoulder positioning with controlled diameter and length tolerances for consistent alignment in assemblies
• High hardness rating of Rockwell C32 ensures long-term durability and wear resistance under repetitive stress
• Broad compliance with ASME B18.3, RoHS 3, and REACH standards for assured quality and environmental safety

Professional Applications & Engineering Value

This alloy steel shoulder screw with a black oxide finish and Class 3A thread fit is engineered to address critical assembly challenges in high-stress environments. The 1/2"-13 UNC coarse thread design ensures rapid installation and robust holding power, minimizing the risk of loosening in vibrating machinery. The precisely machined shoulder provides stable bearing surfaces for rotating components like gears and pulleys, reducing misalignment and wear. With a socket head and knurled texture, it enables efficient torque application in confined spaces, making it ideal for automotive, aerospace, and industrial equipment where high tensile strength and dimensional accuracy are paramount. Its compliance with ASME B18.3 and environmental regulations guarantees reliability in global supply chains.

Specification Summary & Compliance

This shoulder screw adheres to strict dimensional tolerances, including a Class 3A thread fit for precision engagement and shoulder diameter tolerance of -0.004" to -0.002". It meets ASME B18.3 specifications under ASTM A574, ensuring consistent manufacturing quality. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards, confirming its safety and environmental responsibility for industrial use.