S-91746A632 4-40 x 3/8" Thumb Screws

Key Features & Benefits at a Glance

• Superior grip and handling with knurled head texture for easy manual tightening/loosening without tools
• Exceptional corrosion resistance thanks to 18-8 stainless steel construction in demanding environments
• High mechanical strength with 80,000 psi tensile strength and Rockwell B85 hardness for reliable performance
• Optimized low-profile design with round head shape for applications with limited clearance space
• Precision threading with Class 2A UNC coarse threads ensuring consistent engagement and vibration resistance
• Environmental compliance meeting RoHS 3 and REACH standards for safe industrial usage
• Versatile partial threading allowing both secure fastening and smooth alignment in assemblies

Professional Applications & Engineering Value

This 4-40 UNC thumb screw addresses critical industrial challenges where tool-free access and corrosion resistance are paramount. The 18-8 stainless steel construction provides excellent durability against moisture, chemicals, and temperature variations, making it ideal for electronics enclosures, medical devices, and instrumentation panels. The low-profile round head with knurled texture delivers secure grip even with gloved hands, while the coarse UNC threading ensures rapid installation and reliable holding power in vibration-prone applications. Its partially threaded design offers precise control during final tightening, preventing cross-threading in delicate components.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit and UNC coarse threading (4-40 size). The screw features a 3/8" length with 5/16" thread length and right-hand thread direction. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations ensures safe usage across various industries.