S-93791A546 1/4"-20 x 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 for long-lasting performance in harsh environments.
• Exceptional mechanical strength offering 70,000 psi tensile strength and Rockwell B55 hardness to withstand high-stress applications.
• Precise and reliable fastening ensured by Class 3A thread fit and UNC coarse spacing, minimizing the risk of loosening under vibration.
• Efficient installation and flush finish with a standard 82° countersink angle and flat head design, ideal for applications requiring a smooth surface.
• Easy drive engagement using a 5/32" hex drive, providing secure tool grip and reducing slippage during tightening.
• Full threading for maximum grip along the entire 1/2" length, ensuring strong holding power across the entire fastened material.
• Compliance with major industrial standards including ASME B18.3, RoHS 3, and REACH, guaranteeing quality and environmental safety.

Professional Applications & Engineering Value

Engineered for demanding industrial environments, these 1/4"-20 flat head screws are crafted from 18-8 stainless steel with a black-oxide passivated finish to combat corrosion and extend service life in machinery, automotive, and outdoor equipment. The UNC coarse thread with Class 3A fit provides superior resistance to vibration loosening, a common failure point in dynamic assemblies. The flat head with 82° countersink ensures a seamless, flush installation, critical in applications where protrusions are unacceptable. These screws deliver reliable 70,000 psi tensile strength, making them ideal for heavy-duty fastening in structural and mechanical systems where durability and precision are paramount.

Specification Summary & Compliance

This screw features precise inch system dimensions: 1/4"-20 UNC coarse thread with Class 3A fit for tight tolerances, fully threaded along a 1/2" length. It meets ASME B18.3 specifications for dimensional consistency and performance. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring adherence to environmental and safety standards for industrial use.