S-91259A826 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional strength and durability with alloy steel construction and Rockwell C32 hardness for reliable performance in demanding applications.
• Superior corrosion resistance provided by the black oxide finish, extending service life in harsh industrial environments.
• High tensile and shear strength (140,000 psi tensile, 84,000 psi shear) ensures secure fastening under heavy loads and vibrations.
• Precision fit and alignment with Class 3A thread fit and standard shoulder fit, reducing assembly errors and improving mechanical stability.
• Easy installation and removal thanks to the 5/16" hex socket drive and knurled head, allowing for efficient tool engagement and handling.
• Versatile coarse UNC threading (1/2"-13) enables quick assembly and disassembly, ideal for maintenance and adjustment-heavy setups.
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety, quality, and environmental responsibility.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address common industrial challenges such as misalignment, high stress, and corrosion. The black oxide finish enhances resistance to rust and wear, making it suitable for machinery, automotive, and heavy equipment where exposure to moisture and chemicals is frequent. With a 7" shoulder length and precise 5/8" shoulder diameter, it provides stable bearing surfaces for rotating parts, reducing wear and extending component life. The coarse UNC thread and right-hand direction facilitate quick assembly in time-sensitive operations, while the socket head design allows for compact installations in confined spaces. Ideal for pivots, guides, and structural supports, this screw ensures reliable performance in high-strength applications, minimizing downtime and maintenance costs.

Specification Summary & Compliance

This shoulder screw features precise dimensions, including a thread length of 3/4" with Class 3A fit for tight tolerances, and shoulder diameter and length tolerances of -0.004" to -0.002" and -0.005" to 0.005", respectively. It adheres to UNC thread standards and is manufactured in compliance with ASME B18.3 specifications. Additionally, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for global industrial use.