S-91259A442 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 140,000 psi tensile strength and 84,000 psi minimum shear strength, ensuring reliable performance in high-stress applications.
• Superior corrosion resistance from the black oxide finish, extending service life in demanding industrial environments.
• Precision alignment and smooth rotation thanks to the 5/8" shoulder diameter with tight tolerances, reducing wear on mating components.
• High-strength alloy steel construction with Rockwell C32 hardness for excellent durability and resistance to deformation under heavy loads.
• Secure and efficient installation with a 5/16" hex drive and knurled socket head, providing enhanced grip and preventing tool slippage.
• Reliable thread engagement with Class 3A fit and 1/2"-13 UNC coarse threads, offering quick assembly and vibration resistance.
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety and environmental responsibility.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in precision machinery and heavy-duty equipment. The black oxide finish provides a protective layer against rust and corrosion, making it ideal for applications in humid or chemically aggressive environments. The 5/8" shoulder diameter with controlled tolerances ensures exact alignment for rotating parts like bearings, pulleys, and gears, minimizing misalignment and reducing maintenance costs. The 1/2"-13 UNC coarse threads and Class 3A fit deliver secure fastening with high resistance to loosening under vibration, commonly encountered in automotive, aerospace, and industrial automation systems. Combined with a knurled socket head and hex drive, it allows for easy installation in confined spaces, enhancing assembly efficiency while maintaining structural integrity under 140,000 psi tensile strength.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional standards, including a Class 3A thread fit for superior accuracy and a shoulder diameter tolerance of -0.004" to -0.002". It is manufactured in accordance with ASME B18.3 specifications and meets ASTM A574 material requirements. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and safe for various industrial applications.