S-90585A204 4-40 x 1/2" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction and passivated finish, ideal for harsh industrial environments
• Precise thread engagement with Class 3A fit UNC coarse threading ensures reliable fastening and vibration resistance
• High mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for demanding applications
• Optimal flush mounting with standard 82° countersink angle flat head design for clean surface finishes
• Easy installation using standard 1/16" hex drive tools with consistent head diameter tolerances
• Full thread coverage along the 1/2" length provides maximum grip and load distribution
• Regulatory compliance meets ASME B18.3 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

These 316 stainless steel flat head screws with 4-40 UNC coarse threading address critical challenges in industrial fastening where corrosion resistance and mechanical reliability are paramount. The combination of Class 3A thread fit and fully threaded design ensures maximum engagement in thin materials and vibration-prone applications, while the passivated finish enhances surface durability against chemical exposure. Ideal for marine equipment, chemical processing installations, and food machinery, these screws provide long-term performance where standard fasteners would degrade. The hex drive configuration allows for high-torque installation without cam-out, maintaining head integrity during repeated maintenance cycles in industrial fastening systems.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 3A thread fit and UNC coarse thread spacing, these screws maintain tight tolerances including head diameter (-0.037" to 0") and consistent 82° countersink angle. Compliance with ASME B18.3 manufacturing specifications ensures dimensional interoperability, while meeting RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for hazardous substance restrictions. The mechanical properties including 70,000 psi tensile strength and Rockwell B55 hardness are consistently maintained through controlled manufacturing processes.