S-93996A121 4-40 Shoulder Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with permanent nylon patch that maintains secure fastening from -70° to 250°F without compromising thread integrity
• Superior corrosion resistance through 18-8 stainless steel construction, ideal for harsh industrial environments and washdown applications
• Precision shoulder alignment with tight diameter tolerance (-0.001" to 0") and length control (0" to 0.002") for accurate component positioning
• High-strength performance delivering 70,000 psi tensile strength and Rockwell B55 hardness for demanding mechanical applications
• Reliable thread engagement with Class 2A UNC coarse threads ensuring consistent installation and load distribution
• Dual-drive compatibility featuring both socket and slotted head options for flexible installation in confined spaces
• Regulatory compliance meeting RoHS 3 and REACH standards for global industrial supply chain requirements

Professional Applications & Engineering Value

This 4-40 UNC shoulder screw delivers critical engineering solutions where precise component alignment and vibration resistance are paramount. The 1/8" shoulder diameter with precise fit tolerance provides accurate radial positioning for bearings, gears, and linkages in assembly operations. The integrated nylon patch thread locker eliminates the need for separate locking washers or chemical adhesives, maintaining clamp load under extreme vibration conditions from -70° to 250°F. Manufactured from 18-8 stainless steel, this fastener resists corrosion in demanding environments while the coarse UNC threads and Class 2A fit ensure rapid installation with consistent torque values. Ideal for precision machinery, electronic enclosures, and automated systems requiring reliable, maintenance-free fastening solutions.

Specification Summary & Compliance

This shoulder screw maintains Class 2A thread fit per UNC standards with precise shoulder dimensions (1/8" diameter, 3/8" length) and tight tolerances for engineering applications. Manufacturing complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental compliance for industrial and commercial use. The fastener delivers 70,000 psi tensile strength with Rockwell B55 hardness, suitable for mechanical assemblies requiring durable, corrosion-resistant components with integrated vibration resistance.