S-91746A521 1/4"-20 x 1 5/8" Thumb Screws

Key Features & Benefits at a Glance

• Superior grip and torque application with knurled head texture for secure hand-tightening without tools
• Exceptional corrosion resistance from 18-8 stainless steel construction for long-term reliability in harsh environments
• Optimized low-profile design (3/16" head height) for applications with limited clearance while maintaining easy adjustability
• High mechanical strength with 80,000 psi tensile strength and Rockwell B83 hardness for demanding industrial applications
• Precision threading performance with UNC coarse threads and Class 2A fit ensuring smooth engagement and consistent fastening
• Versatile partial threading (1 3/8" thread length) allowing both secure fastening and smooth shaft guidance
• Regulatory compliance assurance meeting RoHS 3 and REACH standards for environmentally responsible manufacturing

Professional Applications & Engineering Value

This low-profile knurled thumb screw delivers exceptional engineering value across industrial applications where tool-free adjustments and reliable fastening are critical. The 18-8 stainless steel construction provides superior corrosion resistance for harsh environments including manufacturing equipment, electronic enclosures, and outdoor machinery. The UNC coarse threading with Class 2A fit ensures quick installation and removal while maintaining precise alignment in repeatedly adjusted assemblies. The knurled head design offers maximum grip even with oily hands or gloves, reducing installation time and eliminating the need for specialized tools. This partially threaded thumb screw is particularly valuable in applications requiring both secure fastening and smooth sliding motion, making it ideal for clamping mechanisms, access panels, and precision instrument adjustments where space constraints demand the low-profile configuration.

Specification Summary & Compliance

This thumb screw features precision 1/4"-20 UNC coarse threading with Class 2A thread fit for consistent engagement and reliable performance. Manufacturing complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring regulatory compliance for industrial and commercial applications worldwide. The dimensional specifications include a 3/4" knurled head diameter, 1 5/8" overall length, and partial threading extending 1 3/8" for optimal fastening versatility.