S-93791A418 1/4"-20 x 1 3/4" 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 environments
• Precise thread engagement with Class 3A fit ensuring reliable fastening and vibration resistance in critical assemblies
• High mechanical strength offering 70,000 psi tensile strength and Rockwell B55 hardness for demanding industrial applications
• Efficient installation with 5/32" hex drive and standard flat head profile for flush mounting and easy torque application
• Optimized thread design using 1/4"-20 UNC coarse spacing for quicker assembly and reduced cross-threading risks
• Versatile partial threading allowing secure clamping while minimizing thread damage in adjustable components
• Regulatory compliance meeting ASME B18.3 standards and RoHS/REACH directives for global industrial use

Professional Applications & Engineering Value

Engineered for precision fastening in industrial machinery, automotive assemblies, and electronic enclosures, these 1/4"-20 UNC flat head screws address critical challenges like vibration loosening and environmental degradation. The 18-8 stainless steel material combined with a black-oxide passivated finish provides exceptional resistance to rust and chemical exposure, extending service life in humid or corrosive settings. The Class 3A thread fit and coarse thread spacing ensure rapid installation with minimal alignment issues, while the 82° countersink angle facilitates seamless flush mounting in predrilled surfaces. With partial threading and 70,000 psi tensile strength, these screws maintain structural integrity under dynamic loads, making them ideal for high-stress mechanical joints where reliability is paramount.

Specification Summary & Compliance

This flat head socket screw features precise Class 3A thread fit per UNC standards with a 1/4"-20 thread size and coarse spacing. Manufacturing adheres to ASME B18.3 specifications, ensuring dimensional accuracy for the flat head profile and 5/32" hex drive. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing environmental safety and material traceability.