S-90273A559 1/4"-28 x 3/4" ASME B18.6.3 Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction for extended service life in demanding environments
• Precise flush mounting achieved through standard 82° countersink angle and flat head design for seamless surface integration
• Enhanced drive stability with Phillips No. 3 drive style providing secure torque transmission and reduced cam-out risk
• Reliable thread engagement through Class 2A UNF fine threads ensuring vibration resistance and consistent clamping force
• Full-length threading delivers maximum grip strength across the entire 3/4" length for superior fastening performance
• Certified mechanical strength with Rockwell B70 hardness providing durable performance under industrial stress conditions
• Global compliance assurance meeting ASME B18.6.3 specifications, RoHS 3, and REACH environmental standards

Professional Applications & Engineering Value

These 1/4"-28 UNF flat head screws deliver exceptional engineering value in applications requiring flush surface mounting and reliable fastening performance. The zinc-plated steel construction provides essential corrosion protection for industrial equipment, machinery assemblies, and outdoor applications where environmental exposure is a concern. The UNF fine thread configuration offers superior vibration resistance compared to coarse threads, making these flat head Phillips screws ideal for precision equipment, automotive components, and electronic enclosures where loosening under dynamic loads must be prevented. The standardized 82° countersink angle ensures proper seating in prepared holes, eliminating protrusions that could interfere with moving parts or create safety hazards in finished assemblies.

Specification Summary & Compliance

Manufactured to exacting inch system dimensions with Class 2A thread fit tolerance for consistent mating with corresponding UNF nuts and threaded holes. These fully threaded screws comply with ASME B18.6.3 mechanical and dimensional specifications, ensuring interchangeability and reliability across industrial applications. Environmental compliance is verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) certifications, confirming the absence of restricted substances for global market acceptance. The standard flat head profile and right-hand thread direction maintain industry-standard installation practices.