S-93791A563 1/4"-20 x 1" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel and black-oxide passivated finish for long-lasting performance in harsh environments
• Exceptional holding power thanks to 70,000 psi tensile strength and Rockwell B55 hardness, ideal for heavy-duty applications
• Precise and reliable fastening with Class 3A thread fit and UNC coarse thread spacing, reducing the risk of cross-threading
• Efficient installation and removal using a standard 5/32" hex drive, providing a secure grip and minimizing tool slippage
• Flush, low-profile seating with a standard flat head and 82° countersink angle for a smooth, finished appearance
• Full-thread engagement along the entire 1" length, ensuring maximum grip and load distribution
• Compliance with major industry standards including ASME B18.3, RoHS 3, and REACH for guaranteed quality and safety

Professional Applications & Engineering Value

These 1/4"-20 flat head screws are engineered to solve critical fastening challenges in demanding industrial environments. The 18-8 stainless steel core provides excellent resistance to rust and corrosion, making them suitable for machinery, outdoor equipment, and applications exposed to moisture or chemicals. The black-oxide passivated finish adds an extra layer of protection while reducing light reflection. The combination of a UNC coarse thread and Class 3A fit ensures quick assembly and a secure, vibration-resistant connection, which is vital for maintaining integrity in automotive, aerospace, and construction assemblies. The hex drive design allows for high torque application, preventing stripping and ensuring the fastener remains securely in place under stress.

Specification Summary & Compliance

This screw features a 1/4"-20 UNC thread with coarse spacing and a precision Class 3A thread fit for consistent performance. Manufacturing and dimensional specifications conform to ASME B18.3. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and safe for use in various industrial and consumer applications.