S-91259A796 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 for reliable performance in high-stress applications.
• Superior corrosion resistance due to the black oxide finish, extending service life in harsh industrial environments.
• Precise alignment and reduced wear achieved through the 5/8" shoulder diameter and standard shoulder fit, minimizing component misalignment.
• High thread reliability with Class 3A thread fit and UNC coarse threads, ensuring secure fastening and easy assembly.
• Enhanced grip and torque application from the knurled socket head and 5/16" hex drive, preventing slippage during installation.
• Consistent durability backed by Rockwell C32 hardness and alloy steel construction, resisting deformation under heavy loads.
• Broad regulatory compliance including ASME B18.3, RoHS 3, and REACH, ensuring safety and environmental standards are met.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in precision machinery, automotive assemblies, and heavy-duty industrial equipment. The black oxide finish provides a protective layer against rust and abrasion, ideal for environments exposed to moisture or chemicals. With a 1/2"-13 UNC thread and Class 3A fit, it offers superior thread engagement, reducing the risk of stripping in high-vibration settings. The 5/8" shoulder diameter and 1-1/4" shoulder length ensure accurate positioning of moving parts, such as in pivoting mechanisms or bearing supports, minimizing wear and maintenance costs. By combining high tensile strength and coarse thread spacing, this screw delivers reliable fastening in applications demanding repeated adjustments and heavy loads, from conveyor systems to robotic arms.

Specification Summary & Compliance

This shoulder screw adheres to strict dimensional tolerances, including a shoulder diameter tolerance of -0.004" to -0.002" and shoulder length tolerance of -0.005" to 0.005". The thread fit conforms to Class 3A standards, while the UNC thread type and coarse spacing ensure compatibility with common industrial components. It meets ASME B18.3 specifications for socket head shoulder screws and is manufactured in compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing environmental safety and material integrity.