S-90279A114 4-40 x 7/8" ASME B18.6.3 Steel Round Head Phillips Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction for extended service life in demanding environments
• Excellent drive stability with Phillips No. 1 drive design preventing cam-out and ensuring secure fastening
• High tensile strength of 60,000 psi provides reliable performance in heavy-duty applications
• Precision thread engagement with Class 2A UNC coarse threads ensuring consistent, vibration-resistant connections
• Optimized load distribution through rounded head design that minimizes surface stress and material damage
• Full threading capability along the 7/8" length allows for maximum adjustability and holding power
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

These 4-40 UNC zinc-plated steel rounded head Phillips screws deliver exceptional engineering value across industrial applications where corrosion resistance and mechanical reliability are paramount. The combination of Rockwell B69 hardness and 60,000 psi tensile strength ensures these fasteners withstand substantial loads without deformation, making them ideal for machinery assembly, electrical enclosures, and construction frameworks. The coarse UNC threading provides superior grip in various materials while the fully threaded design maximizes connection integrity. The zinc plating offers critical protection against environmental factors, significantly extending service life in challenging conditions where moisture and chemical exposure are concerns. These screws solve common industrial pain points including fastener failure, corrosion-induced replacement costs, and installation inefficiency.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerance ensuring consistent performance across applications. Complies with ASME B18.6.3 specifications for dimensional and mechanical requirements. Meets environmental regulations including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) standards, confirming adherence to hazardous substance restrictions. Thread specifications include 4-40 UNC coarse threads with right-hand direction and standard rounded head profile.