S-92949A114 4-40 x 7/8" 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 long-lasting performance in harsh environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness to withstand high-stress applications
• Precise, secure fastening achieved through Class 3A thread fit and UNC coarse threading for reliable engagement and vibration resistance
• Easy, slip-resistant installation with 1/16" hex drive providing positive torque transfer and reduced tool cam-out risk
• Maximum thread engagement with fully threaded design ensuring consistent clamping force along the entire 7/8" length
• Industry-standard compliance meeting ASME B18.3 specifications for dimensional accuracy and interchangeability
• Environmental regulation adherence with RoHS 3 and REACH compliance for safe use in regulated industries

Professional Applications & Engineering Value

These 4-40 UNC thread rounded head screws deliver critical performance advantages for precision assembly applications. The 18-8 stainless steel material combined with passivated finish provides exceptional resistance to oxidation and chemical exposure, making them ideal for electronics, medical devices, and marine equipment where corrosion protection is paramount. The Class 3A thread fit ensures tight tolerances and reliable fastening in vibration-prone environments, while the button head design offers a low-profile appearance with improved clearance. The hex drive configuration allows for high-torque installation without stripping, and the coarse thread spacing facilitates quick assembly in production line settings. These screws solve common industrial challenges including fastener failure, thread stripping, and corrosion-induced degradation.

Specification Summary & Compliance

This rounded head screw features precise dimensional control with Class 3A thread fit per UNC standards, ensuring superior thread engagement and mechanical integrity. Manufacturing adheres to ASME B18.3 specifications for dimensional accuracy and performance reliability. The product maintains full compliance with RoHS 3 (2015/863/EU) restrictions on hazardous substances and REACH (EC 1907/2006) regulations for chemical safety. Thread specifications include 4-40 UNC coarse thread with right-hand direction and full threading along the 7/8" length, providing consistent fastening performance across industrial applications.