S-90585A854 5/8"-11 x 3 1/2" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance in harsh environments thanks to 316 stainless steel construction with passivated finish
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for demanding applications
• Precision thread engagement with Class 3A fit and UNC coarse threading ensuring reliable fastening performance
• Full-length threading provides maximum grip and load distribution across the entire fastener length
• Standardized dimensions per ASME B18.3 ensure compatibility and interchangeability in industrial assemblies
• Easy installation and removal with 3/8" hex drive design for efficient torque application
• Regulatory compliance with RoHS 3 and REACH standards for environmentally responsible manufacturing

Professional Applications & Engineering Value

This 316 stainless steel flat head screw delivers critical performance advantages in corrosive and high-stress environments. The combination of marine-grade 316 stainless steel with passivated surface treatment provides exceptional protection against saltwater, chemicals, and atmospheric corrosion, making it ideal for marine equipment, chemical processing plants, and coastal infrastructure. The 5/8"-11 UNC coarse threading with Class 3A precision fit ensures rapid installation and secure fastening in structural applications, while the flat head design with 82° countersink creates flush surfaces for safety and aesthetics. With 70,000 psi tensile strength and full threading, this fastener maintains integrity under vibration and heavy loads, solving common failure points in industrial machinery, offshore platforms, and processing equipment.

Specification Summary & Compliance

This flat head screw maintains Class 3A thread fit tolerance per UNC standards with precise dimensional control including head diameter tolerance of -0.076" to 0". Manufacturing complies with ASME B18.3 specifications for consistent quality and performance. The product is RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting current environmental regulations for hazardous substances. Threading follows UNC coarse thread standard with right-hand direction and features a standard flat head profile with 82° countersink angle for proper seating in matched countersunk holes.