S-93791A417 1/4"-20 x 7/8" 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, ideal for harsh industrial environments
• Exceptional mechanical strength offering 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 risk
• Efficient installation and flush mounting thanks to the standard flat head with 82° countersink angle and 5/32" hex drive
• Full-thread design provides consistent holding power along the entire 7/8" length for versatile applications
• Compliance with major standards including ASME B18.3, RoHS 3, and REACH, guaranteeing quality and environmental safety
• Durable surface treatment enhances wear resistance and maintains performance under demanding conditions

Professional Applications & Engineering Value

These 1/4"-20 x 7/8" flat head screws are engineered to address common industrial challenges such as vibration loosening, corrosion, and high-stress demands. The 18-8 stainless steel material, combined with a black-oxide passivated finish, provides excellent resistance to rust and chemicals, making them suitable for machinery, automotive, and outdoor equipment. The UNC coarse threading and Class 3A thread fit ensure quick assembly and reliable performance in coarse-thread applications, while the flat head design allows for a smooth, flush surface in countersunk holes. This screw is ideal for applications requiring high tensile strength and durability, reducing maintenance needs and downtime in industrial fastening systems.

Specification Summary & Compliance

This screw features precise dimensions including a 0.531" head diameter, 0.161" head height, and Class 3A thread fit for accurate assembly. It adheres to ASME B18.3 standards for flat head screws, with UNC coarse threads (1/4"-20 size) and an 82° countersink angle. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets environmental and safety requirements for industrial use.