S-91259A118 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior tensile and shear resistance with 140,000 psi tensile strength and 84,000 psi minimum shear strength for reliable performance in high-stress applications.
• Enhanced corrosion protection and reduced galling thanks to the black oxide finish, extending service life in demanding industrial environments.
• Precise Class 3A thread fit ensures tight, secure fastening with minimal backlash, ideal for assemblies requiring exact alignment.
• Rockwell C32 hardness provides excellent wear resistance and durability, maintaining integrity under repeated loads.
• Knurled socket head with 5/16" hex drive offers improved grip and easy installation, even in confined spaces.
• Accurate shoulder dimensions with controlled tolerances support consistent positioning and smooth rotation in pivot and bearing applications.
• Compliance with ASME B18.3, RoHS 3, and REACH guarantees adherence to industry standards and environmental regulations for safe, global use.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address common challenges in precision machinery, such as misalignment and component wear. The 1/2"-13 UNC coarse thread with Class 3A fit ensures rapid assembly and reliable clamping force, reducing installation time in production lines. Its black oxide finish not only resists corrosion but also minimizes friction in rotating parts, making it ideal for pivot points, linkages, and bearing supports. The precisely machined shoulder diameter and length with tight tolerances provide stable alignment, preventing lateral movement and extending the life of connected components. Commonly used in automotive, aerospace, and industrial equipment, this screw delivers consistent performance where high tensile and shear strength are critical, supported by Rockwell C32 hardness for long-term durability in dynamic applications.

Specification Summary & Compliance

This shoulder screw features a 1/2"-13 UNC coarse thread with Class 3A thread fit for high precision, and shoulder dimensions include a diameter of 5/8" (tolerance: -0.004" to -0.002") and length of 1/2" (tolerance: -0.005" to 0.005"). Manufactured to ASME B18.3 specifications using ASTM A574 alloy steel, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance standards, ensuring environmental safety and regulatory adherence for industrial use.