S-90298A158 8-32 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 environments and extended service life.
• Precise alignment and stability from the substantial 1-1/2" shoulder, minimizing component misalignment and wear.
• Secure and reliable fastening with Class 3A thread fit and UNC coarse thread, ensuring high vibration resistance and load distribution.
• Easy and flush installation using the internal hex socket drive, allowing for high torque application in confined spaces.
• Guaranteed dimensional accuracy and interchangeability, manufactured to meet strict ASME B18.3 specifications.
• Environmental and regulatory compliance with RoHS 3 and REACH, making it safe for various industrial and international markets.
• Versatile right-hand thread design for standard assembly processes, compatible with common UNC 8-32 nuts and tapped holes.

Professional Applications & Engineering Value

This stainless steel shoulder screw is engineered to solve critical alignment challenges in precision machinery, automation systems, and rotating assemblies. The long 1-1/2" shoulder acts as a precise pivot or axle, maintaining exact component positioning and reducing shear stress on the 8-32 UNC thread. The 18-8 stainless steel material combined with a passivated finish provides excellent resistance to oxidation and chemical exposure, ensuring reliability in demanding conditions. The hex socket drive allows for secure installation with standard tools, preventing cam-out and damage to the screw head. Ideal for applications where dimensional stability and corrosion resistance are paramount, this screw delivers consistent performance in assembly jigs, bearing mounts, and linkage systems.

Specification Summary & Compliance

This shoulder screw features a 8-32 UNC Class 3A thread with a thread length of 3/16" and a shoulder diameter of 3/16" (tolerance: -0.001" to 0.001"). The shoulder length is 1-1/2" (tolerance: -0.005" to 0.005") with a standard shoulder fit. It conforms to ASME B18.3 dimensional standards and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring it meets industry requirements for safety and performance.