S-93310A535 1/4"-20 x 3/8" ASME B18.3, ASTM F879, MIL-DTL-18240 Thread-Locking Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior vibration resistance with a nylon patch thread locker that maintains secure fastening in high-motion environments
• Excellent corrosion resistance provided by 18-8 stainless steel construction, ideal for harsh or outdoor industrial settings
• High tensile strength of 70,000 psi ensures reliable load-bearing capacity and joint integrity under stress
• Precise Class 3A thread fit for smooth assembly and reduced risk of cross-threading in UNC coarse thread applications
• Wide temperature tolerance from -70° to 250°F allowing consistent performance in extreme thermal conditions
• Easy installation and removal with a hex drive design that offers superior torque transfer and tool engagement
• Fully threaded shank for maximum grip length and uniform clamping force across the entire fastener

Professional Applications & Engineering Value

This 1/4-20 UNC nylon patch locking screw is engineered to address critical challenges in industrial assembly, such as vibration-induced loosening and environmental degradation. The 18-8 stainless steel material provides inherent resistance to rust and chemical exposure, making it suitable for machinery, automotive, and marine applications. The nylon patch acts as a durable locking element that does not harden or degrade over time, ensuring reusable security without compromising the coarse thread engagement. Combined with a rounded button head and hex drive, this screw offers a low-profile, high-strength fastening solution that reduces maintenance cycles and enhances equipment reliability in demanding settings.

Specification Summary & Compliance

The screw features a Class 3A thread fit per UNC standards, ensuring precise dimensional accuracy and interchangeability. It complies with ASME B18.3, ASTM F879, and MIL-DTL-18240 specifications for consistent manufacturing quality. Environmental and safety adherence is confirmed through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, supporting sustainable and safe usage in global supply chains.