S-90273A578 5/16"-18 x 1/2" ASME B18.6.3 Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction for extended service life in harsh industrial environments
• Exceptional holding power with 60,000 psi tensile strength and Rockwell B70 hardness for reliable fastening in demanding applications
• Optimized flush installation featuring 82° countersink angle and undercut head design for seamless surface finishing
• Enhanced driving efficiency with Phillips No. 4 drive style ensuring secure tool engagement and reduced cam-out
• Reliable thread engagement through Class 2A fit UNC coarse threads providing vibration resistance and quick assembly
• Full-length threading offering maximum grip length and versatility across various material thicknesses
• Regulatory compliance assurance meeting ASME B18.6.3 specifications and environmental standards including RoHS 3 and REACH

Professional Applications & Engineering Value

These 5/16"-18 UNC flat head Phillips screws deliver critical engineering solutions for industrial assembly challenges. The zinc-plated steel construction provides essential corrosion protection in manufacturing facilities, construction sites, and metalworking applications where environmental exposure is a concern. The fully threaded design with coarse UNC threads ensures rapid installation and superior pull-out resistance in wood, metal, and composite materials. The undercut flat head profile combined with the precise 82° countersink angle creates flush-mounted connections that eliminate protrusions in machinery, automotive components, and structural assemblies. These industrial screws maintain integrity under vibration and load stresses, making them ideal for permanent fastening in equipment manufacturing, building frameworks, and heavy-duty mechanical applications where reliability cannot be compromised.

Specification Summary & Compliance

Manufactured to exacting ASME B18.6.3 standards, these screws feature precision UNC coarse threads with Class 2A fit tolerance for consistent threading performance. The 5/16"-18 thread size with 0.313" diameter and 1/2" length ensures dimensional accuracy across production batches. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations confirms environmental responsibility and material safety for global industrial applications.