S-91259A872 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black oxide finish, extending service life in harsh industrial environments.
• Exceptional strength and durability from alloy steel construction and Rockwell C32 hardness, resisting wear and deformation under heavy loads.
• Precise alignment and smooth rotation with a 5/8" shoulder diameter and standard shoulder fit, reducing component wear.
• Reliable, vibration-resistant fastening thanks to Class 3A thread fit and coarse 1/2"-13 UNC threads for quick assembly.
• Secure, non-slip installation with a knurled socket head and 5/16" hex drive, allowing high torque application.
• Broad compliance and quality assurance meeting ASME B18.3 and ASTM A574 standards, ensuring interchangeability and performance.
• Environmentally safe usage with RoHS 3 and REACH compliance, suitable for regulated industries.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical alignment and load-bearing challenges in machinery and automation systems. The black oxide finish provides a protective layer against rust and corrosion, making it ideal for applications in humid or chemically aggressive settings. With a 1/2"-13 UNC coarse thread and Class 3A thread fit, it ensures tight, secure fastening that resists loosening under vibration, common in conveyor systems, robotic arms, and precision equipment. The knurled socket head and hex drive design facilitate easy installation in confined spaces, while the precisely machined shoulder offers stable support for rotating parts like bearings and pulleys, reducing misalignment and extending component life. This screw delivers reliable performance in industrial applications requiring high strength and dimensional accuracy.

Specification Summary & Compliance

This shoulder screw adheres to strict dimensional tolerances, including a Class 3A thread fit for precise engagement and a shoulder diameter tolerance of -0.004" to -0.002". It conforms to ASME B18.3 and ASTM A574 specifications, ensuring consistent quality and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing it is free from hazardous substances for safe use in various industries.