S-91099A461 4-40 x 3/4" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with passivated 18-8 stainless steel construction for extended service life in harsh environments
• Exceptional mechanical strength with 80,000 PSI tensile strength and Rockwell B80 hardness for reliable load-bearing performance
• Precision thread engagement through Class 2A thread fit and UNC coarse threads ensuring secure fastening and vibration resistance
• Optimized flush mounting with undercut flat head profile and 82° countersink angle for seamless surface integration
• Enhanced drive stability with Phillips No. 1 drive system preventing cam-out during installation
• Full-threaded design providing maximum grip length and uniform stress distribution across the entire 3/4" length
• Regulatory compliance assurance meeting ASME B18.6.3 specifications and environmental standards (RoHS 3, REACH)

Professional Applications & Engineering Value

These 4-40 UNC flat head Phillips screws deliver critical performance advantages for industrial assembly applications where reliability and corrosion resistance are paramount. The passivated 18-8 stainless steel construction provides exceptional protection against oxidation and chemical exposure, making them ideal for electronics enclosures, machinery components, and outdoor equipment. The undercut flat head profile with 82° countersink angle ensures flush mounting without protrusion, while the coarse UNC threads and Class 2A fit provide rapid installation and secure fastening in various materials. With 80,000 PSI tensile strength and full threading, these screws maintain structural integrity under vibration and dynamic loads, solving common fastener failure points in demanding industrial environments.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit and UNC coarse threading (4-40) ensuring consistent performance. The 3/4" length features complete threading for maximum engagement. These flat head screws strictly conform to ASME B18.6.3 mechanical and dimensional specifications, with full compliance to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, guaranteeing they meet current industrial safety and sustainability requirements.