S-90275A105 4-40 x 3/16" ASME B18.6.3 Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction for extended service life in demanding environments
• Enhanced flush mounting capability due to undercut flat head design that sits perfectly flush with surfaces
• Excellent thread engagement with fully threaded UNC coarse pattern ensuring secure fastening in various materials
• Reliable installation control through slotted drive compatibility with standard tools and Rockwell B70 hardness
• Precise fit and interchangeability guaranteed by Class 2A thread fit meeting ASME B18.6.3 specifications
• Optimized countersinking performance with 82° head angle for smooth, professional-grade installations
• Compliance with global standards including RoHS 3 and REACH for safe, environmentally responsible usage

Professional Applications & Engineering Value

These 4-40 UNC zinc-plated steel flat head screws deliver critical engineering solutions where flush surface mounting and corrosion resistance are paramount. The undercut flat head profile eliminates protrusion issues in precision assemblies, while the coarse thread design provides superior holding power in softer materials and vibration-prone environments. Manufactured to ASME B18.6.3 standards with Rockwell B70 hardness, these fully threaded screws maintain structural integrity under stress, making them ideal for industrial fastening applications in electronics, machinery, and automotive components where reliability cannot be compromised.

Specification Summary & Compliance

These flat head slotted screws feature precise Class 2A thread fit with UNC coarse threading (4-40 size) and 82° countersink angle. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy and performance. The products are fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting international environmental and safety regulations for industrial use.