S-92949A108 4-40 x 3/8" ASME B18.3 Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance through 18-8 stainless steel construction and passivated finish, ensuring long-term reliability in harsh environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for demanding load-bearing applications
• Precision thread engagement with Class 3A fit and UNC coarse threads providing secure fastening and vibration resistance
• Optimized installation efficiency featuring 1/16" hex drive design for positive torque transmission and reduced tool slippage
• Comprehensive regulatory compliance meeting ASME B18.3 standards while being RoHS 3 and REACH compliant for global industrial use
• Full-threaded design maximizing grip length and distribution of clamping force across the entire fastener length
• Streamlined rounded button head profile offering low-clearance installation with smooth, finished appearance

Professional Applications & Engineering Value

Engineered for precision assembly requirements, these 4-40 UNC thread rounded head screws deliver critical performance advantages in industrial fastening systems. The 18-8 stainless steel composition combined with passivated finish creates a robust barrier against chemical exposure and atmospheric corrosion, significantly extending service life in manufacturing equipment, electronic enclosures, and marine applications. The hex drive design ensures reliable torque transmission during installation, preventing cam-out incidents that can damage components. With Class 3A thread fit and coarse thread spacing, these fasteners maintain secure connections in high-vibration environments while facilitating quicker assembly than fine-thread alternatives. The fully threaded configuration provides consistent clamping force distribution, making them ideal for securing panels, brackets, and machinery components where uniform pressure is critical.

Specification Summary & Compliance

This rounded head screw maintains precision Class 3A thread fit per UNC standards with coarse thread spacing for optimal engagement. Manufacturing conforms to ASME B18.3 specifications, ensuring dimensional accuracy and performance reliability. Regulatory compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) requirements, confirming environmental safety and material restrictions adherence for global industrial distribution.