S-93310A338 1/4"-20 x 1 1/2" ASME B18.3, ASTM F879, MIL-DTL-18240 Thread-Locking Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking: Nylon patch thread locker maintains secure fastening in high-vibration environments, preventing loosening under dynamic loads.
• Exceptional corrosion resistance: Made from 18-8 stainless steel, offering reliable performance in humid, chemical, and outdoor applications without rusting.
• High mechanical strength: With 70,000 psi tensile strength and Rockwell B55 hardness, it withstands heavy loads and repeated stress without failure.
• Wide temperature tolerance: Thread locker functions effectively from -70° to 250°F, ensuring stability in extreme thermal conditions.
• Precise thread engagement: Class 3A thread fit and UNC coarse threading provide accurate, quick installation and superior holding power.
• Easy installation and removal: Hex drive (5/32") allows for high-torque application with standard tools, reducing assembly time and tool slip.
• Low-profile rounded head: Button head design minimizes protrusion, reducing snag risks and providing a clean, finished appearance.

Professional Applications & Engineering Value

This nylon patch locking rounded head screw is engineered to solve critical challenges in industrial and mechanical assemblies where vibration-induced loosening and corrosion are major concerns. The 18-8 stainless steel construction ensures long-term durability in harsh environments, such as marine equipment, food processing machinery, and outdoor structures. The fully threaded design with coarse UNC threads enables rapid installation and strong grip in softer materials or where high clamp load is required. Combined with the hex drive, it allows for efficient torque transmission, reducing the risk of stripping and improving workflow efficiency in automated or manual assembly lines. This fastener is ideal for securing components in automotive, aerospace, and electronics enclosures, where reliability and compliance with stringent specifications are non-negotiable.

Specification Summary & Compliance

This screw features a 1/4"-20 UNC thread with Class 3A fit for precise tolerance and optimal performance. It is fully threaded and meets key industry standards including ASME B18.3, ASTM F879, and MIL-DTL-18240. The product is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), ensuring it is free from hazardous substances and safe for various industrial applications.