S-91259A806 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 demanding applications.
• Precision alignment and smooth rotation ensured by the 3" shoulder with tight diameter tolerance, reducing wear on mating components.
• Superior corrosion resistance from the black oxide finish, extending service life in harsh industrial environments.
• High-strength alloy steel construction with Rockwell C32 hardness provides excellent durability and fatigue resistance.
• Secure, non-slip installation facilitated by the knurled head and 5/16" hex drive, allowing for high torque application.
• Reliable thread engagement with Class 3A fit and 1/2"-13 UNC coarse thread for quick assembly and vibration resistance.
• Full regulatory compliance with ASME B18.3, RoHS 3, and REACH standards for quality assurance and global market acceptance.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical alignment and pivot point requirements in heavy machinery, automotive assemblies, and precision industrial equipment. The 3" shoulder length with controlled diameter tolerance provides a precise bearing surface that prevents axial movement and reduces bushing wear. The black oxide finish offers consistent corrosion protection where lubricants are applied, while the 1/2"-13 UNC coarse thread with Class 3A fit ensures rapid installation and maintains clamp load under dynamic stresses. Its knurled socket head design enhances grip during high-torque fastening, making it ideal for applications requiring repeated adjustments or exposure to vibration, such as in conveyor systems, robotic arms, and manufacturing jigs.

Specification Summary & Compliance

This shoulder screw features precision Class 3A thread fit with UNC coarse threading and maintains tight shoulder diameter tolerance of -0.004" to -0.002". Manufactured in compliance with ASME B18.3 specifications and ASTM A574 material standards, it ensures consistent dimensional accuracy. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental and safety regulations for industrial components.