S-91259A477 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional strength and durability with 140,000 psi tensile strength 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.
• Precise alignment and smooth rotation ensured by the Class 3A thread fit and standard shoulder fit, reducing wear and assembly time.
• Secure and easy installation with a 5/32" hex drive and knurled head for improved grip and torque application.
• Broad compatibility with 1/4"-20 UNC coarse threads, making it suitable for a wide range of machinery and equipment.
• High dimensional accuracy with tight tolerances on shoulder diameter and length, ensuring consistent performance in precision assemblies.
• Compliance with industry standards including ASME B18.3 and ASTM A574, guaranteeing quality and reliability for professional use.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address common industrial challenges, such as misalignment and component wear in rotating assemblies. The black oxide finish enhances corrosion resistance, making it ideal for environments exposed to moisture and chemicals. With a 1/4"-20 UNC coarse thread and Class 3A fit, it provides secure fastening and precise positioning in machinery, automotive, and aerospace applications. The 7/16" shoulder length acts as a pivot or spacer, reducing friction and extending the life of connected parts. Its high tensile strength and Rockwell C32 hardness ensure it withstands heavy loads and vibrations, offering long-term reliability and reduced maintenance costs.

Specification Summary & Compliance

This shoulder screw features precise dimensions, including a shoulder diameter tolerance of -0.004" to -0.002" and length tolerance of -0.005" to 0.005", with a Class 3A thread fit for high accuracy. It adheres to ASME B18.3 and ASTM A574 standards, ensuring consistent manufacturing quality. Additionally, it is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmentally safe and regulated industrial use.