S-90291A858 1/4"-28 ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Superior vibration resistance through the green nylon 6/6 plastic tip that maintains secure positioning even under dynamic loads
• Non-marring surface protection with the soft nylon tip that prevents damage to shafts and components during installation and use
• Reliable performance in extreme temperatures with a nylon tip rated for -50° to 250°F, ensuring consistent grip across industrial environments
• Excellent corrosion resistance provided by 18-8 stainless steel construction, ideal for harsh or humid operating conditions
• Precise thread engagement with Class 3A UNF fine threads for tighter tolerances and reduced risk of loosening
• Easy installation and removal using the 1/8" hex drive, allowing for high torque application in confined spaces
• Long-term durability supported by Rockwell B80 hardness, resisting wear and deformation under repeated use

Professional Applications & Engineering Value

This 1/4"-28 UNF nylon tip set screw is engineered to address common industrial challenges such as component slippage, surface damage, and fastener failure due to vibration. The 18-8 stainless steel body offers robust corrosion resistance, while the green nylon 6/6 plastic tip acts as a resilient buffer that absorbs shocks and prevents marring on precision shafts, pulleys, and gears. Its fine thread design and Class 3A thread fit ensure minimal backlash and higher clamping force, making it ideal for applications in machinery, automotive assemblies, and electronic enclosures where vibration resistance and repositioning accuracy are critical. The headless and hex drive configuration allows for flush mounting and tool access in tight spaces, enhancing design flexibility.

Specification Summary & Compliance

This set screw adheres to ASME B18.3 specifications, with a Class 3A thread fit for precise dimensional accuracy and consistent performance. It is manufactured from 18-8 stainless steel with a Rockwell B80 hardness and features a UNF fine thread (1/4"-28) with right-hand direction. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets environmental and safety standards for industrial and international use.