S-90279A561 1/4"-28 x 1/2" ASME B18.6.3 Steel Round Head Phillips Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, extending service life in demanding industrial environments
• Enhanced load-bearing capacity from 60,000 psi tensile strength and Rockwell B69 hardness for reliable performance under stress
• Precise, secure fastening ensured by Class 2A thread fit and UNF fine threading, minimizing loosening in vibration-prone applications
• Optimized installation efficiency with No. 3 Phillips drive and rounded head design, reducing tool slippage and assembly time
• Maximum grip and holding power through fully threaded 1/2" length, distributing clamping force evenly across the entire fastener
• Regulatory compliance assurance meeting ASME B18.6.3 standards, RoHS 3, and REACH for global industrial use without restriction
• Versatile right-hand threading compatible with standard UNF components, simplifying replacements and inventory management

Professional Applications & Engineering Value

Engineered for industrial assembly and machinery maintenance, these zinc-plated steel rounded head screws address critical challenges in vibration resistance and environmental durability. The UNF fine thread configuration provides superior clamping force in thin materials and precision equipment, while the Phillips drive ensures consistent torque application without cam-out. With fully threaded design and Class 2A thread fit, they eliminate weak points in assemblies subjected to dynamic loads. Ideal for electronic enclosures, automotive components, and manufacturing fixtures, these screws deliver reliable performance where corrosion protection and dimensional accuracy are paramount.

Specification Summary & Compliance

This 1/4"-28 UNF screw maintains precise Class 2A thread fit per ASME B18.6.3 manufacturing standards, ensuring interchangeability and consistent performance. The zinc-plated steel construction provides both corrosion resistance and electrical conductivity. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, these screws meet global environmental requirements for hazardous substance restrictions. Dimensional accuracy includes 0.25" thread diameter, 1/2" length, and 0.472" head diameter for uniform installation across applications.