S-97768A420 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction, ideal for harsh industrial environments
• Enhanced durability and wear resistance from the black oxide finish, extending service life
• Precise alignment and reduced wear with a 1/2" shoulder diameter and tight tolerance fit
• High-strength performance delivering 70,000 psi tensile and 35,000 psi shear strength for demanding applications
• Secure, slip-resistant installation thanks to the knurled head and hex socket drive design
• Reliable thread engagement with Class 3A UNC coarse threads ensuring consistent fastening
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH for quality assurance

Professional Applications & Engineering Value

This 5/16"-18 UNC shoulder screw is engineered to address critical alignment and rotational stability challenges in precision machinery, automation systems, and heavy-duty equipment. The 18-8 stainless steel material provides excellent resistance to corrosion and oxidation, while the black oxide finish adds an extra layer of protection against wear and galling. The 1/2" shoulder diameter with tight tolerances ensures precise component positioning, reducing misalignment and vibration in assemblies. With a Class 3A thread fit and coarse UNC threads, it offers quick installation and reliable performance in high-stress environments like robotics, conveyor systems, and industrial fixtures, minimizing downtime and maintenance costs.

Specification Summary & Compliance

This shoulder screw features a 5/16"-18 UNC thread with Class 3A fit for high precision, a shoulder diameter of 1/2" (tolerance: -0.004" to -0.002"), and shoulder length of 3/4" (tolerance: -0.005" to 0.005"). It meets ASME B18.3 specifications and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and industry-standard reliability.