S-91781A440 1/4"-28 x 5/8" ASME B18.6.3 Stainless Steel Slotted Flat Head 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 mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable performance under heavy loads
• Precision thread engagement with Class 2A fit and UNF fine threads ensuring secure fastening and vibration resistance
• Optimal flush mounting with standard 82° countersink angle and flat head design for seamless surface integration
• Full-threaded reliability providing maximum grip length and uniform stress distribution along the entire fastener
• Industry-standard compliance meeting ASME B18.6.3 specifications for dimensional accuracy and performance
• Environmental responsibility with RoHS 3 and REACH compliance for sustainable manufacturing practices

Professional Applications & Engineering Value

These 1/4"-28 UNF flat head slotted screws deliver critical engineering solutions where flush surface mounting and corrosion resistance are paramount. The combination of 18-8 stainless steel material and passivated finish provides exceptional protection against chemical exposure and atmospheric corrosion, making them ideal for marine, chemical processing, and food industry applications. The fine UNF threading and Class 2A thread fit ensure precise engagement in tapped holes, reducing the risk of cross-threading while maintaining consistent clamping force. The fully threaded design offers maximum holding power across the entire 5/8" length, while the standardized 82° countersink angle guarantees proper seating in machined counterbores. These industrial screws solve common fastening challenges where vibration resistance, environmental durability, and dimensional accuracy are critical to operational reliability.

Specification Summary & Compliance

This flat head slotted screw features precision Class 2A thread fit with 1/4"-28 UNF fine threads and right-hand thread direction. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards, ensuring adherence to current environmental regulations for hazardous substances.