S-90273A106 4-40 x 1/4" 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
• High-strength performance with 60,000 psi tensile strength ensuring reliable, vibration-resistant fastening
• Easy installation and removal with Phillips No. 1 drive design for efficient assembly operations
• Optimal flush mounting featuring standard 82° countersink angle for seamless surface integration
• Consistent thread engagement with fully threaded UNC coarse threads providing maximum holding power
• Precision manufacturing with Class 2A thread fit ensuring reliable mating with standard nuts and components
• Enhanced durability with Rockwell B70 hardness maintaining structural integrity under repeated use

Professional Applications & Engineering Value

These 4-40 UNC flat head screws deliver exceptional engineering value for industrial applications requiring reliable, low-profile fastening solutions. The zinc-plated steel construction provides essential corrosion protection in manufacturing environments, while the 82° countersink angle ensures flush mounting that prevents snagging and maintains clean surface profiles. The coarse thread design offers superior performance in softer materials and faster installation times, making them ideal for production line efficiency. With full threading along the entire 1/4" length, these screws distribute clamping force evenly, reducing stress concentration points. The combination of 60,000 psi tensile strength and Rockwell B70 hardness ensures these fasteners maintain integrity in vibration-prone applications, from machinery assembly to electronic enclosures, providing long-term reliability that reduces maintenance frequency and downtime.

Specification Summary & Compliance

Manufactured to exacting standards, these screws feature Class 2A thread fit tolerance for consistent performance with standard mating components. The product fully complies with ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Environmental and safety compliance is assured through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) certifications, confirming the absence of restricted substances. The right-hand UNC coarse threads (4-40) provide reliable fastening performance across industrial applications, backed by comprehensive quality assurance.