S-91185A825 1/4"-28 x 5/8" Thumb Screws

Key Features & Benefits at a Glance

• Corrosion-resistant 18-8 stainless steel construction ensures long-term reliability in humid or demanding environments, reducing replacement costs and maintenance downtime.
• Ergonomic multi-lobe acetal plastic head provides comfortable, tool-free hand tightening and loosening, speeding up assembly and adjustments without specialized equipment.
• Precision Class 3A thread fit delivers secure, vibration-resistant fastening with minimal risk of cross-threading, enhancing joint integrity in critical applications.
• Fully threaded 5/8" length offers consistent engagement across the entire fastener, allowing flexible positioning and uniform clamping force.
• Fine UNF 1/4"-28 threads enable finer adjustment control and higher tensile strength compared to coarse threads, ideal for precision assemblies.
• RoHS 3 and REACH compliance guarantees adherence to strict environmental and safety regulations, supporting sustainable and globally accepted manufacturing practices.
• Wide operating temperature range (32° to 180°F) ensures stable performance in varied climates, from cool storage to warm operational settings.

Professional Applications & Engineering Value

This 1/4"-28 UNF thumb screw combines the durability of 18-8 stainless steel with the user-friendly design of a black acetal plastic multi-lobe head, addressing common industrial challenges like frequent adjustments and corrosion. The fine thread spacing and Class 3A thread fit provide exceptional precision, reducing the risk of stripping in sensitive equipment such as electronic enclosures, optical devices, and machinery panels. Its fully threaded design ensures consistent hold across the shank, while the right-hand thread direction aligns with standard assembly practices for intuitive use. Ideal for applications requiring quick access without tools—like prototyping, maintenance covers, and instrumentation—this screw enhances efficiency and reduces tool dependency in industrial thumb screw applications.

Specification Summary & Compliance

This thumb screw adheres to UNF thread standards with a Class 3A thread fit for high precision and tight tolerances. Key dimensions include a 1/4"-28 thread size, 5/8" length, and 1 1/2" head diameter. It is manufactured in compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for global supply chains. The inch system of measurement and fully threaded design further support consistent performance in standardized assemblies.