S-91500A343 1/4"-28 x 1/2" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 Stainless Steel construction and passivated finish, ideal for harsh environments and extended service life
• Exceptional mechanical strength offering 70,000 psi tensile strength and Rockwell B80 hardness for reliable performance under high-stress conditions
• Precise, secure fastening with Class 2A thread fit and UNF fine threads (1/4"-28) ensuring vibration resistance and reduced loosening
• Efficient installation and flush finish thanks to the standard 82° countersink angle and No. 3 Phillips drive for easy, countersunk seating
• Full-threaded design providing maximum grip and load distribution along the entire 1/2" length
• Compliance with industry standards including ASME B18.6.3 for dimensional accuracy and RoHS 3/REACH for environmental safety
• Versatile flat head profile enabling seamless, low-profile integration in assemblies where protruding fasteners are not feasible

Professional Applications & Engineering Value

This 1/4"-28 UNF flat head Phillips screw in 316 Stainless Steel is engineered to address critical challenges in demanding industrial settings. Its passivated finish enhances corrosion resistance, making it suitable for marine, chemical processing, and outdoor applications where moisture and corrosive agents are prevalent. The fine UNF threads and Class 2A fit ensure tight, secure connections that resist vibration-induced loosening in machinery, automotive, and aerospace assemblies. The flat head with 82° countersink allows for a smooth, flush surface, preventing snagging and improving aesthetic integration in precision equipment. Fully threaded for uniform stress distribution, it supports high-strength requirements (70,000 psi tensile) in structural frameworks, ensuring long-term reliability and reduced maintenance needs.

Specification Summary & Compliance

This screw adheres to Class 2A thread fit per UNF standards, ensuring precise dimensional tolerances for consistent performance. It meets ASME B18.6.3 specifications for mechanical and dimensional integrity, and complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming its suitability for global industrial use without hazardous substances.