S-91259A479 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional durability and corrosion resistance with a black oxide finish, ideal for harsh industrial environments.
• Superior load-bearing capacity thanks to alloy steel construction and 140,000 psi tensile strength for reliable performance under stress.
• Precise assembly and alignment ensured by the Class 3A thread fit and standard shoulder fit, reducing wear and misalignment.
• Easy installation and removal with a 5/32" hex drive and knurled head for improved grip and torque application.
• Wide compatibility and interchangeability due to UNC coarse threads and compliance with ASME B18.3 standards.
• Long service life and reduced maintenance from Rockwell C32 hardness, resisting deformation in demanding applications.
• Safe and eco-friendly use as it meets RoHS 3 and REACH regulations, ensuring compliance in global markets.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address common industrial challenges, such as component misalignment and mechanical failure. The black oxide finish provides a protective layer against rust and wear, extending the screw's lifespan in humid or corrosive settings. With a 1/4"-20 UNC coarse thread and Class 3A fit, it offers tight tolerances for secure fastening in machinery, automotive assemblies, and precision equipment. The knurled head and hex drive facilitate quick installation, reducing downtime in production lines. Ideal for pivots, spacers, and rotating parts, this screw ensures stable performance in high-stress applications, backed by its 140,000 psi tensile strength and consistent shoulder dimensions for accurate positioning.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional standards, including a Class 3A thread fit and UNC thread type for reliable engagement. The shoulder diameter tolerance is -0.004" to -0.002", and shoulder length tolerance is -0.005" to 0.005", ensuring high accuracy. It conforms to ASME B18.3 specifications and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing safety and environmental responsibility in industrial use.