S-91259A798 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 shear strength for reliable performance in high-stress applications.
• Superior wear resistance and durability thanks to Alloy Steel construction and Rockwell C32 hardness, ensuring long service life.
• Precise alignment and reduced assembly wear achieved through the standard shoulder fit with controlled diameter and length tolerances.
• Corrosion-resistant black oxide finish provides enhanced protection against rust in demanding industrial environments.
• Easy installation and high torque application enabled by the 5/16" hex drive and knurled head for secure grip.
• Accurate and secure fastening with Class 3A thread fit and 1/2"-13 UNC coarse threads, minimizing cross-threading risks.
• Compliance with major industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety and regulatory adherence.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in precision machinery and heavy-duty assemblies. The black oxide finish not only resists corrosion but also reduces friction during installation, while the knurled head and hex drive allow for efficient torque application without slippage. Its 1/2"-13 UNC coarse threads and Class 3A thread fit ensure quick, secure fastening in applications like rotating shafts, pivots, and jigs, where exact alignment and high shear strength are paramount. By combining robust tensile strength with a standardized shoulder diameter, it minimizes misalignment and wear, making it ideal for automotive, aerospace, and industrial equipment sectors that demand reliability under dynamic loads.

Specification Summary & Compliance

This shoulder screw features precise dimensions, including a shoulder diameter tolerance of -0.004" to -0.002" and length tolerance of -0.005" to 0.005", ensuring consistent performance. Threads adhere to UNC coarse standards with a Class 3A fit for tight tolerances. Manufactured in compliance with ASME B18.3 specifications and meeting RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, it guarantees environmental safety and industrial reliability.