S-91771A577 1/4"-20 x 6" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with Passivated 18-8 Stainless Steel construction, ideal for humid or chemically aggressive environments
• High tensile strength of 80,000 psi ensures reliable load-bearing capacity in demanding structural applications
• Rockwell B80 hardness provides superior durability and resistance to wear during installation and long-term use
• Partially threaded UNC coarse thread design delivers optimal clamping force and vibration resistance in wood, metal, and composite materials
• 82° countersink angle and flat head profile allows for flush mounting, reducing snagging hazards and improving aesthetic finish
• Class 2A thread fit guarantees consistent, easy assembly with standard nuts and tapped holes while maintaining secure fastening
• Phillips No. 3 drive enables efficient installation with common tools, minimizing slippage and operator fatigue

Professional Applications & Engineering Value

This 1/4"-20 x 6" Flat Head Phillips Machine Screw is engineered to address critical challenges in industrial and construction settings where corrosion resistance, high tensile strength, and reliable fastening performance are paramount. The Passivated 18-8 Stainless Steel material combats rust and chemical degradation, making it suitable for outdoor infrastructure, marine equipment, and food processing machinery. Its partially threaded coarse UNC thread ensures maximum grip in softer materials while preventing loosening under dynamic loads. The flat head with 82° countersink provides a smooth, flush surface for conveyor systems, architectural metalwork, and assembly lines, eliminating protrusions that could cause injury or impede operation. By integrating ASME B18.6.3 specifications, this screw meets rigorous dimensional and mechanical standards, delivering consistent performance in high-stress applications.

Specification Summary & Compliance

This machine screw adheres to ASME B18.6.3 standards for dimensional accuracy and mechanical properties, with Class 2A thread fit ensuring precise interchangeability. The UNC 1/4"-20 coarse thread and partial threading up to 1 1/2" provide controlled engagement depth. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming the absence of hazardous substances for safe use across global markets.