S-91773A117 4-40 x 1 1/4" ASME B18.6.3 Stainless Steel Round Head Phillips Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance from 18-8 stainless steel construction with passivated finish, ideal for harsh industrial environments
• Exceptional mechanical strength with 100,000 psi tensile strength and Rockwell B100 hardness for reliable load-bearing performance
• Precision thread engagement with Class 2A thread fit and UNC coarse threads ensuring secure fastening and vibration resistance
• Optimized installation efficiency through Phillips No. 1 drive and rounded head design for smooth, cam-out resistant driving
• Full-length threading provides maximum grip and holding power across the entire 1-1/4" length
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations including RoHS 3 and REACH
• Versatile industrial application with right-hand thread direction suitable for various assembly and manufacturing requirements

Professional Applications & Engineering Value

These 4-40 UNC coarse thread screws deliver critical engineering value in demanding industrial environments where corrosion resistance and mechanical reliability are paramount. The 18-8 stainless steel composition, enhanced by passivated finish, provides exceptional protection against chemical exposure and atmospheric corrosion, significantly extending service life in manufacturing equipment, electronic enclosures, and outdoor applications. The rounded head design with Phillips drive facilitates quick installation while minimizing surface damage, making them ideal for assembly lines requiring efficient fastening cycles. The coarse threading ensures secure engagement in various materials, preventing loosening under vibration while the Class 2A thread fit maintains precise tolerances for consistent performance across production runs.

Specification Summary & Compliance

This rounded head screw features precise 4-40 UNC coarse threads with Class 2A thread fit tolerance, ensuring reliable engagement and interchangeability. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy and performance standards. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, containing no restricted substances above threshold limits. The fully threaded design provides consistent fastening capability along the entire 1-1/4" length, while the right-hand thread direction follows industry-standard installation protocols.