S-93791A573 1/4"-20 x 1 1/2" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and black-oxide passivated finish, ideal for harsh industrial environments
• Exceptional mechanical strength delivering 70,000 psi tensile strength and Rockwell B55 hardness for reliable, heavy-duty fastening
• Precise thread engagement with UNC coarse threading and Class 3A fit, ensuring secure connections and reduced cross-threading risks
• Optimized flush mounting featuring a standard flat head with 82° countersink angle for seamless, low-profile installations
• Efficient installation and removal using a 5/32" hex drive, providing superior torque transmission and tool accessibility
• Full threading along the 1-1/2" length for maximum grip and adjustability in various material thicknesses
• Compliance with major industry standards including ASME B18.3, RoHS 3, and REACH for guaranteed quality and environmental safety

Professional Applications & Engineering Value

This 1/4"-20 flat head screw is engineered to address critical challenges in industrial assembly and machinery. The 18-8 stainless steel material, combined with a black-oxide passivated finish, provides excellent resistance to corrosion and oxidation, making it suitable for outdoor, marine, and chemical-exposed applications. The UNC coarse thread design and Class 3A fit ensure rapid installation and high vibration resistance, reducing assembly time and maintenance needs. Its fully threaded body and 82° countersink angle allow for secure, flush mounting in metal, wood, and composite materials, preventing snagging and improving aesthetics. These screws are ideal for heavy-duty frameworks, automotive components, and electrical enclosures where durability and regulatory compliance are paramount.

Specification Summary & Compliance

This flat head screw adheres to ASME B18.3 dimensional standards, with a Class 3A thread fit for precise tolerance and reliable performance. The UNC coarse thread (1/4"-20) and full threading ensure consistent engagement. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of hazardous substances. Manufactured from 18-8 stainless steel, it meets mechanical properties including 70,000 psi tensile strength and Rockwell B55 hardness, suitable for demanding industrial fastening tasks.