S-90298A621 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, ideal for harsh industrial environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for heavy-duty applications
• Precision alignment capability through 3/8" shoulder diameter with tight ±0.001" tolerance for accurate component positioning
• Reliable thread engagement with Class 3A UNC coarse threads ensuring secure fastening in demanding applications
• Enhanced installation control featuring knurled head texture and 3/16" hex drive for positive grip during assembly
• Industry-standard compliance meeting ASME B18.3 specifications for consistent performance and interchangeability
• Environmental responsibility with RoHS 3 and REACH compliance for sustainable manufacturing practices

Professional Applications & Engineering Value

This high-precision shoulder screw delivers exceptional engineering value in applications where component alignment and corrosion resistance are critical. The 18-8 Stainless Steel construction with passivated finish provides superior protection against oxidation and chemical exposure, making it ideal for industrial machinery, automation systems, and precision assemblies operating in demanding environments. The precisely machined 3/8" shoulder diameter with tight ±0.001" tolerance ensures accurate bearing surfaces and proper component spacing, while the Class 3A UNC coarse threads (5/16"-18) offer reliable fastening in high-vibration applications. The combination of 70,000 psi tensile strength and Rockwell B55 hardness ensures long-term durability in mechanical systems requiring repeated disassembly and reassembly.

Specification Summary & Compliance

This shoulder screw features precision Class 3A thread fit with 5/16"-18 UNC coarse thread spacing and right-hand thread direction. Critical dimensions include shoulder diameter of 3/8" with tolerance of -0.001" to 0.001" and shoulder length of 5/8" with tolerance of -0.005" to 0.005". The fastener strictly conforms to ASME B18.3 manufacturing specifications and demonstrates full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring both mechanical reliability and regulatory adherence for industrial applications.