S-92949A105 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 18-8 stainless steel construction and passivated finish for extended service life in harsh environments
• Exceptional thread reliability with Class 3A thread fit ensuring precise engagement and vibration resistance in critical assemblies
• High-strength performance delivering 70,000 psi tensile strength and Rockwell B55 hardness for demanding industrial applications
• Secure installation and removal through hex drive design providing positive torque transmission and reduced tool slippage
• Optimized thread engagement with fully threaded UNC coarse spacing for faster assembly and improved load distribution
• Rounded button head profile offering a low-profile, aesthetically pleasing finish while minimizing snagging hazards
• Regulatory compliance assurance meeting ASME B18.3 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

These 4-40 UNC rounded head screws deliver exceptional engineering value across industrial applications where corrosion resistance, precise thread fit, and reliable fastening are critical. The 18-8 stainless steel material combined with passivated finish provides superior protection against chemical exposure and environmental factors, making them ideal for electronics enclosures, machinery components, and marine equipment. The Class 3A thread fit ensures tight tolerances for vibration-resistant assemblies in precision instruments and automotive systems. With hex drive compatibility and fully threaded coarse spacing, these screws enable rapid installation in high-volume production environments while maintaining consistent clamping force. The rounded button head design offers both aesthetic appeal and safety by eliminating sharp edges in consumer-facing products and equipment interiors.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with Class 3A thread fit precision and UNC coarse thread spacing. These inch-system screws feature 4-40 thread size with 3/16" length and maintain dimensional accuracy throughout production. Compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for global industrial applications requiring hazardous substance restrictions.