S-94128A144 4-40 Shoulder Screws

Key Features & Benefits at a Glance

• High-strength alloy steel construction with Rockwell C32 hardness ensures exceptional durability and resistance to wear in demanding industrial environments
• Precise Class 3A thread fit provides superior assembly accuracy and vibration resistance for critical mechanical applications
• Exact 1/8" shoulder diameter with tight -0.001" to 0" tolerance enables perfect alignment and smooth rotational movement in assemblies
• Coarse UNC 4-40 threading offers faster installation and reduced cross-threading risk compared to fine-thread alternatives
• Headless slotted design allows for flush mounting and easy adjustment in space-constrained applications
• Full regulatory compliance with RoHS 3 and REACH standards ensures environmental safety and global market acceptance
• Right-hand thread direction with standardized UNC pattern provides compatibility with common industrial components and tooling

Professional Applications & Engineering Value

These precision shoulder screws deliver exceptional engineering value in applications requiring exact rotational alignment and reliable fastening. The alloy steel construction with Rockwell C32 hardness provides the necessary strength to withstand high-stress conditions in machinery, automation systems, and precision instruments. The precise shoulder fit with minimal diameter tolerance ensures accurate positioning of moving components, eliminating play and reducing wear in pivot points, bearing mounts, and linkage systems. The 4-40 UNC coarse thread combined with Class 3A thread fit offers superior holding power while facilitating quicker assembly in production environments. The headless slotted configuration makes these shoulder screws ideal for applications where space optimization and clean aesthetics are critical, particularly in consumer electronics, medical devices, and optical equipment where reliable performance and regulatory compliance are paramount.

Specification Summary & Compliance

This 4-40 UNC shoulder screw features Class 3A thread fit precision with exact dimensional control including 1/8" shoulder diameter (-0.001" to 0" tolerance) and 1/2" shoulder length (0" to 0.005" tolerance). Manufactured from high-strength alloy steel with Rockwell C32 hardness, the screw complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial markets. The right-hand coarse thread follows standardized UNC specifications for consistent performance and compatibility.