S-90298A640 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish for extended service life in harsh environments
• Precise component alignment through Class 3A thread fit and controlled shoulder diameter tolerance (±0.001") ensuring reliable assembly
• Exceptional load-bearing capacity with 70,000 psi tensile strength and Rockwell B55 hardness for demanding applications
• Secure installation and removal via hex drive design and knurled head texture providing superior grip during torque application
• Optimized for industrial durability featuring coarse UNC threads and 4" shoulder length for stable rotational movement
• Regulatory compliance assurance meeting ASME B18.3 standards and environmental regulations (RoHS 3/REACH)
• Right-hand thread configuration with standard socket head profile for compatibility with common industrial tools

Professional Applications & Engineering Value

This 18-8 stainless steel shoulder screw delivers critical engineering solutions where precision alignment and rotational stability are paramount. The 4" shoulder length with tight diameter tolerance provides exact bearing surfaces for machinery components, while the Class 3A thread fit ensures secure fastening without play. The passivated finish enhances corrosion resistance in manufacturing environments exposed to moisture or chemicals. Ideal for industrial applications including rotating assemblies, pivot points, and precision machinery, this shoulder screw combines the strength of 70,000 psi tensile rating with the durability of coarse UNC threads that resist stripping. The hex drive and knurled head facilitate installation in confined spaces while preventing tool slippage.

Specification Summary & Compliance

Manufactured to exacting standards with Class 3A thread fit and shoulder diameter tolerance of -0.001" to 0.001". Thread specifications include 5/16"-18 UNC coarse thread with right-hand orientation. Compliant with ASME B18.3 manufacturing specifications and certified for RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Shoulder length maintains -0.005" to 0.005" tolerance for precision applications.