S-90585A358 1/4"-20 x 5/8" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance in harsh environments due to 316 stainless steel construction and passivated finish
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for reliable load-bearing performance
• Precision thread engagement with Class 3A UNC coarse threads ensuring secure, vibration-resistant fastening
• Flush mounting capability with standard 82° countersink angle for smooth surface finishes in assembled products
• Easy installation and removal using standard 5/32" hex drive tools common in industrial maintenance
• Full thread coverage along the 5/8" length provides maximum grip strength in various material thicknesses
• Regulatory compliance assurance meeting ASME B18.3 specifications and environmental standards (RoHS 3, REACH)

Professional Applications & Engineering Value

These 316 stainless steel flat head screws deliver critical performance advantages in demanding applications where corrosion resistance and mechanical reliability are paramount. The combination of UNC coarse threading and Class 3A thread fit ensures rapid assembly with superior vibration resistance, making them ideal for machinery, marine equipment, and chemical processing installations. The passivated finish enhances the inherent corrosion resistance of 316 stainless steel, providing extended service life in humid, saline, or chemically aggressive environments. With their 82° countersink angle and flat head design, these screws create flush surfaces that prevent snagging while maintaining structural integrity under dynamic loads. The fully threaded configuration offers consistent clamping force across the entire fastener length, eliminating weak points in critical assemblies.

Specification Summary & Compliance

This 1/4"-20 x 5/8" flat head screw features precision UNC coarse threads with Class 3A fit tolerance for optimal engagement. Manufacturing complies with ASME B18.3 standards ensuring dimensional accuracy and performance reliability. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, containing no restricted substances. Mechanical properties include 70,000 psi tensile strength and Rockwell B55 hardness, validated through standardized testing protocols.