S-90181A578 5/16"-18 x 1/2" Thumb Screws

Key Features & Benefits at a Glance

• Easy manual operation with spade head design providing maximum surface area for comfortable, high-torque tightening without tools
• Superior thread engagement through full threading ensures consistent grip strength across the entire fastener length
• Reliable performance in demanding applications with 40,000 psi tensile strength and Rockwell B55 hardness
• Quick installation and removal with right-hand coarse UNC threads for fast assembly and disassembly cycles
• Precise thread compatibility with Class 2A fit ensuring consistent performance in standard UNC applications
• Environmental compliance assurance with RoHS 3 (2015/863/EU) compliance for use in regulated industries
• Durable steel construction provides excellent corrosion resistance and long-term reliability in industrial environments

Professional Applications & Engineering Value

This 5/16"-18 UNC steel thumb screw delivers exceptional engineering value through its optimized spade head design and fully threaded construction. The generous 7/8" head width and 11/16" head height provide substantial surface area for manual operation, eliminating the need for tools in applications requiring frequent adjustments or quick access. The coarse UNC thread pattern ensures rapid installation while the Class 2A thread fit maintains precise tolerances for consistent performance. Manufactured from high-strength steel with Rockwell B55 hardness and 40,000 psi tensile strength, this thumb screw withstands repeated use in industrial equipment, machinery panels, electronic enclosures, and assembly jigs where reliable, tool-free fastening is essential for maintenance efficiency and operational continuity.

Specification Summary & Compliance

This thumb screw features 5/16"-18 UNC coarse threads with Class 2A thread fit precision, ensuring compatibility with standard UNC nut and tapped hole applications. The fastener measures 1/2" in length with a thread diameter of 0.313". Manufacturing complies with RoHS 3 (2015/863/EU) environmental regulations, making it suitable for use in electronics, industrial equipment, and other applications requiring compliance with hazardous substance restrictions. The right-hand thread direction and fully threaded design provide consistent engagement throughout the fastener's length.