S-90291A103 4-40 ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Secure Component Protection: Nylon 6/6 plastic tip prevents surface damage and marring, ideal for delicate assemblies.
• Superior Corrosion Resistance: Made from 18-8 Stainless Steel for excellent durability in harsh environments.
• High-Precision Thread Fit: Class 3A thread tolerance ensures tight, reliable fastening with minimal backlash.
• Wide Temperature Suitability: Nylon tip performs reliably from -50° to 250° F, maintaining grip in varied conditions.
• Optimized Drive Engagement: Hex .050" drive provides positive torque transmission and reduces cam-out risk.
• Space-Efficient Headless Design: Allows for flush mounting in confined spaces without protruding hardware.
• Standardized Reliability: Manufactured to ASME B18.3 specifications for consistent quality and interchangeability.

Professional Applications & Engineering Value

This 4-40 UNC set screw with a nylon tip is engineered to solve critical challenges in precision assembly and adjustment applications. The 18-8 Stainless Steel construction offers robust corrosion resistance, essential for machinery, electronics, and automotive components exposed to moisture or chemicals. The coarse UNC thread and Class 3A fit provide rapid installation and high clamping force, reducing assembly time while ensuring vibration resistance. The non-marring nylon 6/6 tip protects sensitive shafts and gears from damage, making it ideal for positioning collars, pulleys, and knobs without compromising the integrity of the engaged surface. Its headless, hex drive design is perfect for applications where space is limited and a clean, flush finish is required, delivering reliable performance in demanding industrial settings.

Specification Summary & Compliance

This set screw adheres to precise dimensional standards with a 4-40 UNC thread size, coarse thread spacing, and a high-accuracy Class 3A thread fit. It conforms to ASME B18.3 manufacturing specifications, ensuring consistent quality and mechanical performance. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing it is free from hazardous substances and safe for use in regulated industries.