S-91185A829 1/4"-28 x 7/8" Thumb Screws

Key Features & Benefits at a Glance

• Quick manual adjustments with the ergonomic multi-lobe thumb head design, eliminating the need for tools in frequent assembly/disassembly applications
• Superior corrosion resistance provided by 18-8 stainless steel construction, ensuring long-term reliability in various industrial environments
• Secure non-marring grip from the black acetal plastic head, protecting sensitive surfaces while offering comfortable hand-tightening
• Precise thread engagement with UNF Class 3A fine threading, delivering excellent vibration resistance and reliable fastening in precision assemblies
• Full-length threading versatility allowing installation at any point along the screw's 7/8" length for flexible positioning
• Wide temperature compatibility with head operation from 32° to 180° F, suitable for most indoor industrial environments
• Environmental compliance assurance meeting RoHS 3 and REACH standards for use in regulated industries and global markets

Professional Applications & Engineering Value

This 1/4"-28 UNF Class 3A thumb screw combines the strength of 18-8 stainless steel with the practical benefits of a multi-lobe black acetal plastic head to solve critical assembly challenges. The fine threading and Class 3A thread fit provide exceptional precision for applications requiring vibration resistance and repeated adjustments, such as electronic enclosures, machinery access panels, and precision instrument calibration. The acetal plastic head offers electrical insulation and prevents surface damage while the fully threaded design ensures maximum engagement in threaded inserts and mounting applications. Engineered for right-hand thread direction and standard UNF threading, this thumb screw delivers reliable performance in maintenance-intensive environments where tool-less operation is essential for efficiency.

Specification Summary & Compliance

This thumb screw features precision 1/4"-28 UNF Class 3A threads with fine thread spacing and right-hand direction. The 18-8 stainless steel body provides excellent corrosion resistance while the black acetal plastic multi-lobe head measures 1 1/2" in diameter with 15/32" height. The component is fully threaded along its 7/8" length and complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for restricted substances.