S-90181A565 1/4"-28 x 3/4" Thumb Screws

Key Features & Benefits at a Glance

• Easy manual installation and removal with the spade head design, eliminating the need for tools in frequent assembly/disassembly applications.
• Superior durability and wear resistance provided by the steel construction and Rockwell B55 hardness, ensuring a long service life.
• High clamping force and load-bearing capability with a tensile strength of 40,000 psi, making it suitable for demanding mechanical applications.
• Precise and reliable thread engagement due to the Class 2A fine UNF threads, minimizing the risk of cross-threading and ensuring a secure fit.
• Maximum grip and holding power along the entire 3/4" length, thanks to the fully threaded design for consistent performance.
• Optimized for right-hand thread applications, conforming to standard assembly practices for broad compatibility.

Professional Applications & Engineering Value

This 1/4"-28 UNF thumb screw is engineered to solve common industrial challenges where tool-less, rapid adjustments are critical. The steel material and Rockwell B55 hardness provide excellent resistance to deformation and wear, making it ideal for high-cycle applications in electronics enclosures, machinery panels, and prototyping fixtures. The spade head offers ample surface area for comfortable hand-tightening, while the fine UNF thread and Class 2A fit ensure precise alignment and vibration resistance in sensitive assemblies. Its fully threaded body guarantees uniform stress distribution, enhancing the screw's reliability in industrial settings where consistent clamping force is paramount.

Specification Summary & Compliance

This thumb screw adheres to the UNF (Unified National Fine) thread standard with a Class 2A tolerance for consistent, precision fits. The specified dimensions include a 1/4"-28 thread size, 3/4" length, and a spade head with a 1/2" height and 23/32" width. Manufactured from high-grade steel, it meets common industry specifications for mechanical fasteners. The product is compliant with RoHS and REACH environmental directives, ensuring it is free from hazardous substances for safe use in various engineering and assembly operations.