S-91185A253 4-40 x 1" Thumb Screws

Key Features & Benefits at a Glance

• Enhanced grip and torque application with a knurled head texture for secure, tool-free hand tightening and loosening in confined spaces.
• Superior corrosion resistance from 18-8 Stainless Steel construction, ensuring long-term reliability in humid or demanding industrial environments.
• Durable, low-friction head made of Acetal Plastic that resists wear, reduces marring on surfaces, and operates effectively from 32° to 180° F.
• Precise and secure fastening with a Class 3A thread fit and 4-40 UNC coarse threads, providing excellent engagement and vibration resistance.
• Optimized for low-clearance applications due to its low-profile, round head design, ideal for panels, electronics, and instruments.
• Partial threading for versatile positioning, allowing flexibility in adjustment depth while maintaining strong holding power.
• Compliance with environmental and safety standards, including RoHS 3 and REACH, ensuring safe use in regulated industries.

Professional Applications & Engineering Value

This 4-40 UNC low-profile thumb screw is engineered to address common challenges in assembly and maintenance, where tool-free access and reliable performance are critical. The combination of an 18-8 stainless steel body and Acetal plastic head offers a balance of strength and lightweight durability, reducing the risk of galvanic corrosion when used with dissimilar metals. The knurled head ensures a firm grip even with gloved hands, speeding up adjustments in industrial equipment, electronic enclosures, and instrumentation. With a coarse thread spacing and Class 3A thread fit, it provides quick installation and high resistance to loosening under vibration, making it ideal for applications requiring repeated access and secure fastening without specialized tools.

Specification Summary & Compliance

This thumb screw adheres to UNC thread standards with a 4-40 thread size and Class 3A thread fit for precision and interchangeability. It is partially threaded with a minimum thread length of 3/4" and features right-hand thread direction. The product is manufactured in compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets stringent environmental and safety requirements for industrial components.