S-8077A638 1/4"-20 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh industrial environments and extended service life.
• Enhanced durability and wear resistance from the black oxide finish, which also provides a sleek, non-reflective appearance.
• Precise alignment and secure pivoting enabled by the smooth, standard-fit shoulder with tight diameter and length tolerances.
• High-strength performance with a tensile strength of 70,000 psi and shear strength of 35,000 psi for demanding applications.
• Secure, non-slip installation thanks to the knurled head and 3/16" hex socket drive, allowing for high torque application.
• Reliable, coarse-thread engagement with the 1/4"-20 UNC thread and Class 3A fit, ensuring vibration resistance and easy assembly.
• Broad regulatory compliance meeting ASME B18.3, RoHS 3, and REACH standards for global industrial use.

Professional Applications & Engineering Value

This 316 stainless steel shoulder screw is engineered to address critical alignment and pivot point challenges in machinery, automation, and assembly fixtures. The black oxide finish enhances corrosion resistance, reducing maintenance in humid or chemically aggressive settings. Its 1/4"-20 UNC coarse thread with a Class 3A fit provides robust, vibration-resistant fastening, while the precision-machined shoulder ensures accurate component positioning, minimizing wear and misalignment. The knurled head and hex socket drive facilitate secure handling and high-torque installation, making it a reliable choice for high-stress applications in robotics, conveyor systems, and precision equipment where 70,000 psi tensile strength is essential for long-term performance.

Specification Summary & Compliance

This shoulder screw features a 1/4"-20 UNC coarse thread with a Class 3A thread fit for precise engagement. The shoulder diameter is 3/8" with a tolerance of -0.004" to -0.002", and the shoulder length is 1 1/4" with a tolerance of -0.005" to 0.005", ensuring consistent alignment. Manufactured to ASME B18.3 specifications, it is also RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting stringent environmental and safety standards for industrial components.