S-98164A429 4-40 x 3/16" ASME B18.3 Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction and passivated finish for extended service life in harsh environments
• Exceptional mechanical strength delivering 70,000 psi tensile strength and Rockwell B55 hardness for reliable load-bearing performance
• Precision thread engagement with Class 3A fit and UNC coarse threads ensuring secure fastening and vibration resistance
• Optimized drive efficiency featuring 1/16" hex drive for maximum torque transmission and reduced tool slippage
• Streamlined installation through fully threaded design enabling consistent clamping force along entire fastener length
• Regulatory compliance assurance meeting ASME B18.3 specifications and environmental standards including RoHS 3 and REACH
• Enhanced accessibility with rounded button head profile providing smooth surface finish and reduced snagging risks

Professional Applications & Engineering Value

These 4-40 UNC thread rounded head screws deliver critical performance advantages in demanding industrial applications where corrosion resistance and mechanical reliability are paramount. The 316 stainless steel material combined with passivated finish provides exceptional protection against chemical exposure and atmospheric corrosion, making these fasteners ideal for marine equipment, chemical processing installations, and food-grade machinery. The Class 3A thread fit ensures precise mating with corresponding nuts and tapped holes, eliminating play while the coarse thread pitch facilitates rapid assembly in production environments. The hex drive configuration allows for high-torque installation without cam-out issues, while the fully threaded design maintains consistent clamping force across the entire engagement length.

Specification Summary & Compliance

Manufactured to exacting dimensional standards with Class 3A thread fit tolerance and UNC coarse thread specifications. These rounded head screws comply with ASME B18.3 mechanical and dimensional requirements, ensuring interchangeability and reliability across industrial applications. Environmental compliance is verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) certifications, confirming restricted substance adherence for global market acceptance.