S-91259A721 3/8"-16 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional durability with 140,000 psi tensile strength and Rockwell C32 hardness, ensuring reliable performance in high-stress industrial applications.
• Superior corrosion resistance from the black oxide finish, extending service life in harsh environments and reducing maintenance needs.
• Precise alignment and secure positioning thanks to the 1/2" shoulder diameter with tight tolerances, minimizing component movement and wear.
• Easy installation and removal with the 1/4" hex socket drive and knurled head, providing a firm grip and reducing tool slippage.
• High thread reliability with Class 3A fit and 3/8"-16 UNC coarse threads, offering excellent vibration resistance and fast assembly.
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety, quality, and environmental responsibility.
• Optimized for heavy-duty use with a minimum shear strength of 84,000 psi, ideal for demanding machinery and equipment assemblies.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in precision industrial applications, such as machinery assembly, automotive systems, and robotics. The black oxide finish provides enhanced corrosion resistance, reducing failure risks in moist or chemically aggressive settings. With its 3/8"-16 UNC coarse threads and Class 3A thread fit, it ensures secure fastening and vibration resistance, minimizing loosening over time. The 1/2" shoulder diameter with controlled tolerances allows for exact component alignment, preventing misalignment and extending equipment lifespan. Ideal for use in high-tensile strength environments, this screw supports efficient maintenance and reliable operation, making it a top choice for engineers seeking durability and compliance in industrial shoulder screws.

Specification Summary & Compliance

This shoulder screw adheres to ASME B18.3 specifications, with precise dimensions including a shoulder diameter tolerance of -0.004" to -0.002" and shoulder length tolerance of -0.005" to 0.005". Threads are 3/8"-16 UNC coarse with a Class 3A fit for high accuracy. It meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, ensuring environmental safety and regulatory adherence in industrial applications.