S-91746A116 4-40 x 3/8" Thumb Screws

Key Features & Benefits at a Glance

• Superior hand-tightening grip with knurled head texture for secure installation without tools
• Exceptional corrosion resistance from 18-8 stainless steel construction in harsh environments
• High-strength performance with 80,000 psi tensile strength and Rockwell B85 hardness
• Optimized low-profile design for applications with limited clearance requirements
• Precision threading with Class 2A UNC coarse threads ensuring reliable engagement
• Partial threading configuration providing enhanced holding power in assembly applications
• Full regulatory compliance meeting RoHS 3 and REACH environmental standards

Professional Applications & Engineering Value

This 4-40 UNC thumb screw delivers exceptional engineering value through its 18-8 stainless steel composition, providing reliable corrosion resistance in demanding industrial environments. The low-profile knurled head design addresses common assembly challenges by enabling quick installation and removal without specialized tools, while maintaining secure fastening in vibration-prone applications. The coarse UNC threading and Class 2A thread fit ensure consistent engagement across multiple installations, making these thumb screws ideal for electronic enclosures, machinery panels, and precision instruments where frequent access is required. The partial threading configuration provides superior clamping force while preventing over-insertion in sensitive components.

Specification Summary & Compliance

This thumb screw features precision 4-40 UNC coarse threads with Class 2A thread fit tolerances, ensuring consistent performance across industrial applications. The fastener maintains dimensional accuracy with a 3/8" length and 5/16" thread length configuration. Manufacturing compliance includes adherence to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming the absence of restricted substances while delivering reliable performance in global markets.