S-90179A552 1/4"-20 x 2 1/2" Thumb Screws

Key Features & Benefits at a Glance

• Enhanced manual torque application with spade head design for comfortable, tool-free tightening and loosening
• Superior load distribution and stability thanks to the integrated flange that acts as a built-in washer
• High-strength performance under stress with a tensile strength of 40,000 psi for demanding industrial environments
• Excellent durability and wear resistance provided by the steel construction and Rockwell B55 hardness
• Quick and reliable coarse thread engagement with UNC 1/4"-20 threading for faster assembly in a wide range of materials
• Precise and consistent fit ensured by the Class 2A thread fit, reducing cross-threading and ensuring smooth installation
• Maximum grip along the entire length due to the fully threaded 2 1/2" shank for secure fastening in deep applications

Professional Applications & Engineering Value

This 1/4"-20 thumb screw is engineered to solve common assembly challenges where tool access is limited or where frequent adjustments are necessary. The steel construction and Rockwell B55 hardness provide the necessary durability to withstand repeated use without stripping or deforming. The spade head offers a large surface area for hand tightening, eliminating the need for tools in applications like access panels, machinery guards, and electronic enclosures. The flange increases the bearing surface, preventing the screw from pulling through softer materials and providing a more secure, vibration-resistant joint. Combined with the UNC coarse thread and Class 2A fit, this screw ensures rapid installation and reliable performance in industrial maintenance, manufacturing, and equipment assembly, reducing downtime and improving operational efficiency.

Specification Summary & Compliance

This thumb screw conforms to Unified National Coarse (UNC) thread standards with a Class 2A tolerance for a consistent, free-fitting assembly. The product is fully threaded with a right-hand thread direction. Manufacturing adheres to standard industrial practices for inch fasteners. The screw is made from standard steel and is typically compliant with general industry regulations; specific compliance with standards such as RoHS or REACH should be confirmed based on the exact material grade and plating used.