S-91259A843 5/8"-11 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength – With 140,000 psi tensile strength and 84,000 psi shear strength, this screw withstands extreme loads and reduces the risk of mechanical failure in demanding applications.
• Precision Shoulder for Accurate Alignment – The 3/4" shoulder diameter with tight tolerances ensures precise component positioning, minimizing misalignment and wear in assemblies.
• Superior Corrosion Resistance – Black oxide finish provides enhanced protection against rust and corrosion, extending service life in harsh industrial environments.
• High-Strength Alloy Steel Construction – Made from alloy steel with Rockwell C32 hardness, offering excellent durability and resistance to deformation under stress.
• Class 3A Thread Fit for Secure Fastening – UNC coarse threads with Class 3A fit ensure reliable, vibration-resistant connections, reducing loosening in high-stress operations.
• Knurled Socket Head for Non-Slip Grip – The knurled head and hex drive design allow for easy installation and removal with standard tools, improving assembly efficiency.
• Compliance with Industry Standards – Meets ASME B18.3 specifications and is RoHS 3 and REACH compliant, ensuring quality and environmental safety for global supply chains.

Professional Applications & Engineering Value

This 5/8"-11 UNC shoulder screw is engineered to address critical alignment and load-bearing challenges in industrial machinery, automation systems, and heavy equipment. The alloy steel construction, combined with a black oxide finish, provides robust resistance to wear and corrosion, making it ideal for environments exposed to moisture, chemicals, or high stress. The precision 3/4" shoulder diameter with controlled tolerances ensures accurate shaft positioning in pulleys, gears, and rotating assemblies, reducing friction and premature component failure. With its coarse UNC threads and Class 3A fit, it delivers secure fastening in applications subject to vibration, such as automotive fixtures, conveyor systems, and manufacturing jigs. By integrating high tensile and shear strength, this screw enhances reliability in industrial shoulder screw applications, supporting efficient production and reduced maintenance downtime.

Specification Summary & Compliance

This shoulder screw adheres to ASME B18.3 manufacturing standards, with precise dimensional controls including a shoulder diameter tolerance of -0.004" to -0.002" and shoulder length tolerance of -0.005" to 0.005". The UNC thread system features a Class 3A fit for high precision, and the product complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for international industrial use.