S-91327A136 1/4"-20 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Secure Vibration Resistance: Integrated nylon patch thread locker prevents loosening under dynamic loads, maintaining assembly integrity in high-vibration environments from -50° to 250°F.
• Superior Corrosion Resistance: Constructed from 18-8 stainless steel, offering excellent durability against rust and chemical exposure in harsh industrial settings.
• High Load-Bearing Capacity: With a 70,000 psi tensile strength and Rockwell B55 hardness, this screw ensures reliable performance under heavy mechanical stress.
• Precision Alignment & Smooth Rotation: Features a standard shoulder with tight diameter and length tolerances for accurate component positioning and reduced wear.
• Easy Installation & Grip: Knurled socket head with hex drive allows for secure tool engagement and manual handling, speeding up assembly processes.
• Wide Regulatory Compliance: Meets ASME B18.3 specifications and is RoHS 3 and REACH compliant, ensuring safety and environmental standards for global supply chains.
• Optimized Thread Fit: Class 3A UNC coarse threads provide a precise, strong fit for quick assembly and enhanced thread engagement in various materials.

Professional Applications & Engineering Value

This 1/4"-20 UNC shoulder screw is engineered to address common industrial challenges such as component misalignment and vibration-induced failure. The 18-8 stainless steel material delivers corrosion resistance, ideal for applications in moist or chemical-exposed environments like machinery, automotive assemblies, and electronic enclosures. The nylon patch locking feature secures the right-hand thread against loosening, making it perfect for rotating parts and equipment subjected to constant motion. Combined with the knurled socket head for easy installation, this screw ensures reliable performance in high-tensile scenarios, reducing maintenance needs and downtime in industrial shoulder screw applications.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional standards, including a Class 3A thread fit for accurate engagement and UNC coarse threading for efficient assembly. It conforms to ASME B18.3 manufacturing specifications, ensuring consistent quality and performance. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing it meets environmental and safety requirements for industrial use.