S-93310A323 2-56 x 1/4" 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: Permanent nylon patch ensures reliable fastening in high-vibration environments, eliminating the need for separate locking hardware.
• Exceptional corrosion resistance: Made from 18-8 Stainless Steel for long-lasting performance in harsh or corrosive conditions.
• High-strength durability: With a 70,000 psi tensile strength and Rockwell B55 hardness, this screw withstands significant mechanical stress.
• Wide operational temperature range: The nylon patch lock functions reliably from -70° to 250° F, making it suitable for diverse industrial climates.
• Precise and secure thread engagement: Class 3A thread fit with UNC coarse threads provides superior tolerance control for a tight, secure connection.
• Easy installation and removal: The hex drive (0.050") and rounded button head design allow for efficient torque application with standard tools.
• Full thread coverage: The screw is fully threaded along its 1/4" length, maximizing grip and load distribution in the application.

Professional Applications & Engineering Value

This 2-56 UNC Nylon Patch Lock Screw is engineered to solve critical fastening challenges in industrial and precision assemblies. The core of its value lies in the combination of the 18-8 stainless steel material, which offers excellent corrosion resistance, and the integrated nylon patch locking technology. This design directly addresses the common industrial problem of fastener loosening due to vibration or thermal cycling, which can lead to equipment failure and costly downtime. The coarse thread (UNC) ensures quick assembly and is less prone to clogging in demanding environments. Its rounded button head and hex drive provide a low-profile, high-strength fastening solution that is ideal for applications in electronics, machinery, automotive sub-assemblies, and aerospace components where reliability is non-negotiable.

Specification Summary & Compliance

This screw features a Class 3A thread fit for high-precision applications, conforming to the UNC 2-56 thread standard. It is manufactured to meet the dimensional and performance requirements of ASME B18.3, ASTM F879, and MIL-DTL-18240. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free of hazardous substances and suitable for global industrial supply chains.