S-91771A553 1/4"-20 x 2 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, ideal for harsh industrial environments.
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable, long-term performance.
• Optimized for flush mounting thanks to the standard flat head profile and 82° countersink angle.
• Secure and efficient installation with a Phillips No. 3 drive, designed to prevent cam-out during high-torque applications.
• Versatile coarse UNC threading (1/4"-20) ensures quick assembly and robust holding power in various materials.
• Precision-engineered fit with Class 2A thread tolerance for consistent, reliable engagement.
• Compliance with major industry standards including ASME B18.6.3, RoHS 3, and REACH for guaranteed quality and safety.

Professional Applications & Engineering Value

This 1/4"-20 UNC flat head screw is engineered to address common industrial challenges such as material fatigue and environmental degradation. The passivated 18-8 stainless steel provides excellent resistance to oxidation and chemical exposure, making it suitable for applications in machinery, outdoor equipment, and assembly lines where moisture or corrosive agents are present. The partially threaded design concentrates clamping force precisely where needed, reducing stress on components and preventing joint failure. Combined with a coarse thread and Phillips drive, it ensures rapid, secure installation in wood, metal, and plastic substrates, streamlining production and maintenance workflows while upholding structural integrity under heavy loads.

Specification Summary & Compliance

Manufactured to exacting dimensional standards, this screw features a Class 2A thread fit for consistent assembly and a 2 3/4" length with a minimum thread length of 1 1/2". It conforms to ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free of hazardous substances and safe for use in regulated industrial and consumer applications.