S-91500A911 1/4"-20 x 1/2" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance from 316 stainless steel construction with passivated finish, ideal for harsh industrial environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B80 hardness for reliable performance under load
• Precision thread engagement with Class 2A thread fit and UNC coarse threads ensuring secure fastening and vibration resistance
• Optimized flush mounting featuring undercut flat head design with 82° countersink angle for seamless surface integration
• Enhanced driving efficiency with No. 3 Phillips drive providing positive torque transfer and reduced cam-out risk
• Full-threaded reliability delivering maximum grip length and uniform stress distribution along the entire fastener
• Regulatory compliance assurance meeting ASME B18.6.3 specifications and environmental standards including RoHS 3 and REACH

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these 1/4"-20 UNC flat head screws solve critical fastening challenges in corrosive environments. The 316 stainless steel composition provides exceptional resistance to chemicals, saltwater, and industrial atmospheres, while the passivated finish enhances surface durability and prevents galling. The undercut flat head profile ensures proper seating in countersunk holes, eliminating protrusion issues in precision assemblies. With coarse UNC threads and Class 2A thread fit, these screws deliver reliable performance in vibration-prone equipment, machinery, marine hardware, and chemical processing systems where corrosion resistance and mechanical integrity are paramount.

Specification Summary & Compliance

This flat head Phillips screw features precision 1/4"-20 UNC coarse threads with Class 2A thread fit per ASME standards, ensuring consistent dimensional accuracy and proper mating with corresponding nuts and threaded holes. Manufacturing complies with ASME B18.6.3 specifications for dimensional requirements and mechanical properties. The product meets RoHS 3 (2015/863/EU) compliance for hazardous substance restrictions and REACH (EC 1907/2006) requirements for chemical safety, making it suitable for global industrial applications with stringent regulatory demands.