S-93791A422 5/16"-18 x 1" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance from 18-8 stainless steel construction, ideal for harsh environments and long-term reliability.
• Superior thread engagement and stripping resistance due to the precise Class 3A thread fit, ensuring secure and reliable fastening.
• High-strength performance under load with a 70,000 psi tensile strength and Rockwell B55 hardness for demanding applications.
• Enhanced durability and wear resistance provided by the black-oxide, passivated finish, which also adds a sleek, professional appearance.
• Efficient installation and removal with the 3/16" hex drive, offering a secure grip and reducing the risk of tool slippage.
• Optimal flush mounting thanks to the standard flat head profile with an 82° countersink angle, creating a smooth surface finish.
• Full threading for maximum grip length and consistent holding power across the entire fastener length.

Professional Applications & Engineering Value

This 5/16"-18 UNC Flat Head Socket Cap Screw is engineered to solve critical challenges in industrial assembly and machinery. The 18-8 Stainless Steel material provides excellent resistance to oxidation and corrosion, making it suitable for applications in marine, chemical processing, and outdoor equipment where environmental factors are a concern. The black-oxide, passivated finish not only enhances aesthetic appeal but also adds an extra layer of protection against wear and galling. With a Class 3A thread fit and coarse UNC threading, these screws ensure quick assembly and high vibration resistance, reducing maintenance needs in automotive, aerospace, and heavy machinery frameworks. The fully threaded design and 82° countersink angle allow for seamless integration into countersunk holes, providing a flush finish that minimizes protrusion and improves safety in moving parts.

Specification Summary & Compliance

This fastener adheres to strict dimensional and performance standards, including a Class 3A thread fit for superior precision and UNC coarse threading (5/16"-18) for reliable engagement. It is manufactured in compliance with ASME B18.3 specifications, ensuring consistent quality and interchangeability. Additionally, the product is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, confirming its safety for use in regulated industries without hazardous substances.