S-90179A634 3/8"-16 x 2 1/2" Thumb Screws

Key Features & Benefits at a Glance

• Enhanced torque application with a large spade head design for comfortable hand-tightening without tools
• Superior load distribution and vibration resistance from the integrated flange, preventing surface damage and loosening
• Exceptional durability and wear resistance provided by the steel construction with a Rockwell B55 hardness
• High mechanical strength for demanding applications, backed by a 40,000 psi tensile strength
• Reliable and fast assembly with a Class 2A coarse (UNC) thread that resists cross-threading and ensures easy engagement
• Maximum grip and holding power along the entire 2-1/2" length due to the fully threaded design
• Wide compatibility with standard 3/8"-16 UNC components, simplifying inventory and replacement

Professional Applications & Engineering Value

This steel thumb screw is engineered to solve critical challenges in industrial assembly and maintenance. The flanged spade head design provides a larger contact surface, distributing clamping force effectively to protect sensitive components from crushing and resist loosening under vibration. The coarse UNC thread and Class 2A fit enable rapid installation and removal, even in environments where debris might clog finer threads, significantly reducing assembly time. Made from high-strength steel and heat-treated to Rockwell B55, it withstands repeated use and high tensile loads up to 40,000 psi, making it an ideal, durable fastener for machinery panels, access covers, and fixtures in manufacturing, automotive, and electronics sectors.

Specification Summary & Compliance

This thumb screw conforms to UNC (Unified Coarse) thread standards with a Class 2A thread fit for consistent, reliable engagement. Key dimensional specifications include a 3/8"-16 thread size, a 2-1/2" length that is fully threaded, a 13/16" head width, and a 0.688" flange diameter. The component is manufactured from steel and meets typical industry standards for mechanical properties, including the specified Rockwell B55 hardness and 40,000 psi tensile strength.