S-8077A799 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.
• Exceptional mechanical strength offering 70,000 psi tensile and 35,000 psi shear strength for reliable performance under high-stress conditions.
• Precise Class 3A thread fit ensures secure, vibration-resistant fastening with 1/4"-20 UNC coarse threading for easy assembly.
• Enhanced durability and wear resistance from the black oxide finish and Rockwell B79 hardness, reducing maintenance needs.
• Secure, non-slip installation facilitated by the knurled socket head and 5/32" hex drive, allowing for high-torque application.
• Accurate component alignment with a consistent 5/16" shoulder diameter and 9/32" shoulder length, minimizing assembly errors.
• Full regulatory compliance with ASME B18.3, RoHS 3, and REACH standards, ensuring safety and environmental responsibility.

Professional Applications & Engineering Value

This 316 stainless steel shoulder screw is engineered to address critical challenges in precision machinery, automation systems, and heavy-duty equipment. The black oxide finish enhances corrosion resistance, making it suitable for moist or chemically aggressive environments, while the UNC coarse thread and Class 3A fit provide reliable, vibration-resistant connections that withstand dynamic loads. The knurled socket head with a hex drive ensures secure tool engagement, reducing the risk of stripping during high-torque installations. Ideal for applications requiring precise axial positioning—such as in bearings, pulleys, and linkages—the consistent shoulder diameter and length facilitate accurate component alignment, minimizing wear and operational downtime. Its high tensile and shear strength ensures long-term reliability in demanding industrial applications, from manufacturing to marine equipment.

Specification Summary & Compliance

This shoulder screw features a 1/4"-20 UNC coarse thread with a Class 3A fit for precise thread engagement, and dimensional tolerances include a shoulder diameter of -0.004" to -0.002" and shoulder length of -0.005" to 0.005". Manufactured in compliance with ASME B18.3 specifications, it also meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulatory requirements, ensuring environmental safety and material integrity.