S-90280A106 4-40 x 1/4" ASME B18.6.3 Steel Fillister Head Slotted Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance through zinc plating, extending service life in demanding industrial environments
• Enhanced durability with Rockwell B69 hardness, maintaining structural integrity under mechanical stress
• Precise thread engagement with Class 2A fit and UNC coarse threads for reliable fastening performance
• Optimized head design featuring high, narrow fillister profile for improved tool engagement and flush mounting
• Full threading capability ensuring maximum grip length and uniform load distribution
• Regulatory compliance meeting ASME B18.6.3 standards and environmental directives (RoHS 3, REACH)
• Versatile installation with slotted drive accommodating standard screwdrivers for easy assembly

Professional Applications & Engineering Value

These 4-40 UNC zinc-plated steel rounded head screws deliver exceptional engineering value in precision assembly applications. The zinc-plated steel construction provides essential corrosion protection for industrial equipment, electronic enclosures, and machinery components exposed to environmental factors. The high, narrow fillister head profile offers superior bearing surface while maintaining a low-profile appearance, crucial for applications with limited clearance. Fully threaded coarse UNC threads ensure rapid installation and secure fastening in various materials, reducing assembly time while maintaining Class 2A thread fit precision. These slotted drive screws are particularly valuable in maintenance applications where traditional driving tools are preferred, making them ideal for aerospace, electronics, and precision instrument assemblies requiring reliable, compliant fastening solutions.

Specification Summary & Compliance

Manufactured to exacting ASME B18.6.3 specifications, these screws feature precise Class 2A thread fit tolerances and UNC coarse thread form with 4-40 thread size. The 1/4" length and fully threaded design ensure consistent performance across applications. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations guarantees safe use in regulated industries, while the Rockwell B69 hardness rating confirms material strength and durability standards are maintained throughout the product lifecycle.