S-91771A539 1/4"-20 x 5/8" 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, ensuring longevity in harsh industrial environments.
• Exceptional mechanical strength with 80,000 PSI tensile strength and Rockwell B80 hardness for reliable performance under high stress.
• Precise and secure fastening thanks to UNC coarse threading and Class 2A thread fit, reducing the risk of cross-threading and ensuring consistent engagement.
• Efficient installation and flush finish with a standard 82° countersink angle and flat head design, ideal for applications requiring a smooth surface.
• Wide compatibility and ease of use with a No. 3 Phillips drive, allowing for quick assembly with common tools.
• Full thread coverage along the 5/8" length for maximum grip and load distribution in various materials.
• Compliance with major industry standards including ASME B18.6.3, RoHS 3, and REACH, ensuring safety and environmental responsibility.

Professional Applications & Engineering Value

This 1/4"-20 x 5/8" Flat Head Phillips machine screw is engineered to address common industrial challenges such as vibration loosening and corrosion in demanding settings. Made from passivated 18-8 stainless steel, it offers excellent resistance to rust and chemicals, making it ideal for machinery, automotive assemblies, and outdoor equipment. The UNC coarse threading and Class 2A fit provide reliable fastening in metals and plastics, while the flat head with an 82° countersink ensures a secure, flush mount that minimizes protrusion risks. With a tensile strength of 80,000 PSI, it supports heavy-duty applications where durability and precision are critical, reducing maintenance needs and enhancing operational efficiency in industrial screws and fastener systems.

Specification Summary & Compliance

This screw features precise Class 2A thread fit and UNC coarse threading (1/4"-20) with a length of 5/8" and full threading for consistent performance. It meets ASME B18.6.3 specifications for dimensional accuracy and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for global industrial use.