S-90251A550 1/4"-28 x 1/4" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking through permanent nylon patch technology, preventing loosening in high-stress applications
• Superior corrosion resistance with 18-8 stainless steel construction, ideal for harsh environments and washdown applications
• Precision thread engagement with Class 3A fit for tighter tolerances and more reliable fastening than standard threads
• Wide temperature performance maintaining locking integrity from -50° to 250°F for industrial and automotive applications
• Secure cup point design creates positive seating and prevents component slippage in permanent assemblies
• High-strength durability with Rockwell B80 hardness for repeated installation and removal without stripping
• Space-saving headless profile with hex drive for flush mounting in confined spaces while providing positive torque application

Professional Applications & Engineering Value

This nylon patch locking set screw delivers critical vibration resistance in demanding applications where traditional fasteners fail. The 18-8 stainless steel construction provides excellent corrosion resistance for outdoor equipment, food processing machinery, and marine applications. The Class 3A UNF fine threads offer superior engagement in softer materials and aluminum components, while the cup point design bites securely into shafts and collars to prevent rotational slippage. Engineers specify this hex drive set screw for permanent assemblies in robotics, automotive systems, and precision machinery where space constraints and vibration are constant challenges. The combination of high-temperature performance and chemical-resistant materials ensures long-term reliability in the most demanding industrial environments.

Specification Summary & Compliance

This 1/4"-28 UNF set screw features precision Class 3A thread fit with fine thread spacing for optimal engagement. Manufactured to ASME B18.3 specifications with consistent dimensional accuracy. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global markets. The nylon patch locking technology maintains performance across the specified temperature range of -50° to 250°F without degradation.