S-91979A658 1/4"-20 x 3/8" Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction, ideal for harsh industrial environments
• Maximum holding power through the cup point design that bites into shafts for secure, permanent fastening
• Enhanced ventilation and pressure relief with the vented tip (0.062" diameter) to prevent binding during installation
• Precise, reliable installation ensured by Class 3A thread fit for tight tolerances and reduced cross-threading risk
• Easy installation in confined spaces using the 1/8" hex drive and headless design for flush mounting
• Durable performance in high-vibration applications with coarse UNC threads providing strong resistance to loosening
• Compliance with global environmental standards including RoHS 3 and REACH for safe, sustainable use

Professional Applications & Engineering Value

This 1/4"-20 UNC set screw is engineered to address critical fastening challenges in industrial machinery, automotive assemblies, and precision equipment. The 18-8 stainless steel material offers excellent resistance to rust and corrosion, extending service life in demanding conditions. The cup point design creates a deep indentation in mating parts, preventing slippage under high torque and vibration. Combined with the vented tip, it allows air and debris escape during tightening, reducing the risk of hydraulic lock and ensuring consistent clamping force. The Class 3A thread fit and coarse thread spacing provide quick assembly and reliable performance in dynamic applications where right-hand threads are standard. Ideal for securing gears, pulleys, and collars, this hex headless screw delivers dependable, long-term fastening solutions for B2B procurement needs.

Specification Summary & Compliance

This set screw features a 1/4"-20 UNC thread with Class 3A fit for high precision and dimensional accuracy. The coarse thread spacing and 0.25" thread diameter adhere to standard inch measurements, while the 1/8" hex drive ensures compatibility with common tools. It is manufactured in compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for environmentally conscious industrial applications without restricted substances.