S-90311A166 1/4"-20 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with permanent nylon patch thread locker that maintains integrity across a wide temperature range from -50° to 250°F
• Superior corrosion resistance thanks to 316 stainless steel construction, ideal for harsh industrial environments and chemical exposure
• Precise alignment capability with standard shoulder fit and controlled diameter tolerance for accurate component positioning
• High-strength performance delivering 70,000 psi tensile strength and 35,000 psi shear strength for demanding applications
• Secure installation with Class 3A thread fit ensuring tight tolerances and reliable fastening in UNC coarse thread applications
• Easy installation and removal with standard hex socket drive (5/32") and knurled head for improved grip during tool operation
• Industry compliance assurance meeting ASME B18.3 specifications while being RoHS 3 and REACH compliant for global applications

Professional Applications & Engineering Value

This 316 stainless steel shoulder screw delivers exceptional engineering value in precision assembly applications where alignment, corrosion resistance, and vibration resistance are critical. The 1/4"-20 UNC coarse thread with Class 3A fit provides superior engagement in various materials, while the integrated nylon patch thread locker eliminates the need for separate locking compounds, reducing assembly time and ensuring permanent vibration resistance. The precision shoulder diameter with tight tolerance control enables accurate positioning of rotating components in machinery, automation systems, and precision instruments. The socket head design with hex drive allows for compact installation in space-constrained applications, making it ideal for industrial equipment, manufacturing fixtures, and automotive assemblies where reliability and precision are paramount.

Specification Summary & Compliance

This shoulder screw features precision Class 3A thread fit with UNC coarse thread specification and maintains dimensional compliance with ASME B18.3 standards. The component demonstrates exceptional dimensional stability with shoulder diameter tolerance of -0.004" to -0.002" and shoulder length tolerance of -0.005" to 0.005". Manufacturing and material compliance includes full adherence to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and global market acceptance. The mechanical properties including Rockwell B79 hardness and specified tensile/shear strengths validate the screw's suitability for high-performance industrial applications requiring reliable fastening solutions.