S-99154A404 4-40 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with 18-8 stainless steel construction, ideal for harsh industrial environments and extended service life.
• Precise component alignment ensured by the 1/8" diameter shoulder with a precise fit tolerance, minimizing assembly play and vibration.
• High-strength performance delivering 70,000 psi tensile strength and Rockwell B55 hardness for reliable load-bearing in demanding applications.
• Simplified installation and maintenance with a combination slotted/socket low-profile head, offering versatile drive options in confined spaces.
• Consistent and reliable threading with UNC coarse 4-40 threads and Class 2A fit, promoting easy assembly and reducing cross-threading risks.
• Compliance with global environmental standards including RoHS 3 and REACH, ensuring material safety and unrestricted international use.
• Optimized for automated assembly featuring a smooth head texture and right-hand thread direction for efficient, high-volume production lines.

Professional Applications & Engineering Value

This 4-40 UNC shoulder screw is engineered to solve critical alignment and durability challenges in precision assemblies. The 18-8 stainless steel material provides excellent resistance to rust and corrosion, making it suitable for machinery, electronics, and automotive components exposed to moisture or chemicals. The 1/8" shoulder diameter and precise shoulder fit act as a built-in locating dowel, ensuring accurate radial positioning of parts like gears, pulleys, and linkages without additional components. This eliminates misalignment, reduces wear, and enhances the overall lifespan of the assembly. The Class 2A thread fit and coarse UNC threading facilitate quick and secure fastening, while the low-profile socket head with a slotted drive offers flexibility for both manual and automated tooling, streamlining production and maintenance processes.

Specification Summary & Compliance

This shoulder screw adheres to UNC thread standards with a Class 2A thread fit for consistent, free-spinning assembly. The shoulder features a diameter of 1/8" with a tolerance of -0.001" to 0" and a length of 3/16" with a tolerance of 0" to 0.002" for precise location. The product is manufactured from 18-8 Stainless Steel and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets stringent environmental and safety standards for industrial use.