S-90273A436 5/16"-18 x 4" 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 demanding environments
• Exceptional holding power with 60,000 psi tensile strength and Rockwell B70 hardness for reliable fastening performance
• Optimized installation efficiency through Phillips No. 4 drive design providing secure tool engagement
• Reduced cross-threading risk with Class 2A thread fit ensuring smooth assembly and consistent performance
• Enhanced material compatibility with UNC coarse thread spacing for superior grip in various substrates
• Streamlined flush mounting with standard 82° countersink angle and flat head profile for clean finished appearances
• Regulatory compliance assurance meeting ASME B18.6.3 specifications and environmental standards

Professional Applications & Engineering Value

These zinc-plated steel flat head screws deliver critical engineering advantages for industrial applications where corrosion resistance and structural integrity are paramount. The partially threaded design concentrates engagement strength where needed most, while the UNC coarse thread spacing provides superior pull-out resistance in wood, plastic, and soft metals. The Phillips No. 4 drive system ensures reliable torque transfer during installation, reducing cam-out incidents that compromise fastener integrity. With 60,000 psi tensile strength and Rockwell B70 hardness, these screws maintain clamping force under vibration and load variations common in machinery, electrical enclosures, and structural assemblies. The standard 82° countersink angle enables seamless flush mounting in predrilled applications, creating professional finishes while maintaining the protective benefits of zinc plating against environmental exposure.

Specification Summary & Compliance

Manufactured to precise Class 2A thread fit tolerances with 5/16"-18 UNC coarse threads and 4" length featuring partial threading over 1-1/2" minimum engagement. These flat head Phillips screws conform to ASME B18.6.3 mechanical standards and demonstrate compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for global industrial applications requiring verified material safety and performance consistency.