S-90337A391 4-40 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel construction and passivated finish, ensuring longevity in harsh industrial environments
• Precise component alignment through the 1" shoulder with tight diameter and length tolerances for reliable assembly positioning
• High-strength performance delivering 70,000 psi tensile strength and Rockwell B55 hardness for demanding applications
• Space-saving low profile design with socket head allowing flush mounting in confined spaces while maintaining 5/64" hex drive accessibility
• Reliable thread engagement with Class 2A UNC coarse threads providing secure fastening and vibration resistance
• Environmental compliance assurance meeting RoHS 3 and REACH standards for safe use across regulated industries
• Optimized installation efficiency combining right-hand thread direction with hex drive for straightforward assembly and maintenance

Professional Applications & Engineering Value

This 4-40 UNC shoulder screw delivers exceptional engineering value in precision assemblies 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 medical equipment, optical instruments, and electronic enclosures operating in demanding conditions. The precisely machined 1" shoulder length with minimal tolerances ensures accurate spacing and rotational control for moving parts, while the low profile socket head maintains a compact form factor without compromising the 5/64" hex drive accessibility. These features collectively solve common industrial challenges of misalignment, corrosion-induced failure, and space constraints in high-precision mechanisms.

Specification Summary & Compliance

This shoulder screw maintains Class 2A thread fit per UNC standards with precise shoulder diameter tolerance of -0.001" to 0" and shoulder length tolerance of 0" to 0.002". Manufacturing complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety. The inch system measurement, right-hand thread direction, and coarse thread spacing provide reliable performance across industrial applications requiring consistent dimensional accuracy and regulatory compliance.