S-8077A641 1/4"-20 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 Stainless Steel construction and Black Oxide finish, ideal for harsh industrial environments and extended service life.
• Exceptional mechanical strength offering 70,000 psi tensile strength and 35,000 psi shear strength for reliable performance in high-stress applications.
• Precise alignment and smooth rotation provided by the 2 1/4" shoulder with tight diameter tolerance, reducing wear on mating components.
• Secure, high-torque installation enabled by the 3/16" hex socket drive and knurled head, preventing slippage during assembly.
• Consistent, reliable threading with Class 3A fit and 1/4"-20 UNC coarse thread profile, ensuring easy assembly and vibration resistance.
• Broad industry compliance meeting ASME B18.3 standards and being RoHS 3 & REACH compliant for global regulatory acceptance.
• Optimized for durability with a Rockwell B79 hardness, providing excellent resistance to deformation under load.

Professional Applications & Engineering Value

This shoulder screw is engineered to address critical alignment and pivot point requirements in demanding industrial applications. The 316 Stainless Steel material, combined with a Black Oxide finish, provides outstanding resistance to corrosion from chemicals, moisture, and salt spray, making it suitable for food processing, marine, and chemical equipment. The precision-machined shoulder acts as a built-in spacer or bearing surface, eliminating the need for additional components and reducing assembly time. The UNC coarse threads and Class 3A thread fit ensure rapid assembly and maintain clamp load in high-vibration environments like machinery, automotive assemblies, and conveyor systems. The socket head with hex drive allows for compact installation in confined spaces, while the knurled head texture offers enhanced grip for manual adjustments. This design provides a robust, long-lasting solution for pivot shafts, linkages, and guide pins where precision and reliability are paramount.

Specification Summary & Compliance

This shoulder screw features a 1/4"-20 UNC thread with a Class 3A fit for precision threading. The shoulder diameter is 3/8" with a tolerance of -0.004" to -0.002", and the shoulder length is 2 1/4" with a tolerance of -0.005" to 0.005", ensuring exact dimensional control. It is manufactured in compliance with ASME B18.3 specifications and is fully RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, confirming its suitability for use in regulated industries and environmentally conscious applications.