S-90298A634 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel and passivated finish, ideal for harsh industrial environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for heavy-duty applications
• Precise thread engagement with Class 3A thread fit ensuring reliable, vibration-resistant connections
• Secure installation and removal featuring knurled head for enhanced grip and hex drive for easy torque application
• Accurate shoulder positioning with tight diameter tolerance (±0.001") and length tolerance (±0.005") for consistent alignment
• Broad compatibility with UNC coarse threads (5/16"-18) meeting ASME B18.3 standards for interchangeability
• Environmental compliance with RoHS 3 and REACH regulations for safe use in regulated industries

Professional Applications & Engineering Value

This 18-8 stainless steel shoulder screw delivers critical performance in precision machinery, automation systems, and rotating assemblies where alignment and durability are paramount. The 2-1/2" shoulder length provides stable bearing surfaces for gears, pulleys, and linkages, while the Class 3A thread fit maintains tight tolerances under dynamic loads. The passivated finish significantly enhances corrosion resistance in humid or chemical-exposed environments, extending service life. Combined with 70,000 psi tensile strength and knurled head design, it solves common challenges of component slippage, misalignment, and premature failure in demanding industrial applications.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with Class 3A thread fit and UNC 5/16"-18 coarse threading. Shoulder diameter tolerance maintained at -0.001" to 0.001" and shoulder length tolerance at -0.005" to 0.005" for precision alignment. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global markets.