S-99926A143 1/4"-20 x 1 1/2" Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B70 hardness for reliable load-bearing performance
• Precision thread engagement through Class 3A thread fit and UNC coarse threads ensuring secure fastening in demanding applications
• Optimized flush mounting with undercut flat head profile and 100° countersink angle for seamless surface integration
• Enhanced installation efficiency with hex drive design providing superior torque transmission and slip resistance
• Regulatory compliance assurance meeting RoHS 3 and REACH standards for environmentally responsible manufacturing
• Versatile partial threading allowing combination of secure thread engagement and unthreaded shank benefits

Professional Applications & Engineering Value

This 18-8 stainless steel flat head screw delivers critical performance advantages in industrial fastening applications where corrosion resistance and mechanical reliability are paramount. The combination of UNC coarse threading with Class 3A precision fit ensures consistent engagement in machinery, equipment assemblies, and structural frameworks subjected to vibration and dynamic loads. The passivated finish provides an additional protective oxide layer, significantly extending service life in chemically aggressive environments. The undercut flat head design with 100° countersink angle facilitates perfect flush mounting in precision-machined components, while the hex drive configuration enables high-torque installation without cam-out issues. These engineering features make it particularly valuable for manufacturing equipment, automotive assemblies, and marine applications where failure prevention and long-term reliability are critical operational requirements.

Specification Summary & Compliance

This fastener maintains Class 3A thread tolerances for precision fitment and features 1/4"-20 UNC coarse threads with right-hand orientation. The partially threaded design provides a 1.36" minimum thread length on the 1-1/2" overall length. Manufacturing compliance includes adherence to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental responsibility and material safety. The mechanical properties guarantee 70,000 psi tensile strength with Rockwell B70 hardness for consistent performance across industrial applications.