S-91440A622 4-40 x 3/8" ASME B18.6.3 Steel Round Head Combination Phillips/Slotted Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, extending service life in humid or industrial environments.
• Enhanced torque transmission through the dual Phillips/Slotted drive, reducing cam-out and tool slippage during installation.
• Reliable thread engagement with Class 2A coarse UNC threads, ensuring quick assembly and vibration resistance in machinery.
• Consistent hardness performance at Rockwell B70, providing excellent durability and resistance to stripping under load.
• Full threading along the 3/8" length for maximum grip and holding power in various material thicknesses.
• Compliance with ASME B18.6.3 standards, guaranteeing dimensional accuracy and interchangeability for industrial use.
• Environmental and safety adherence with RoHS 3 and REACH compliance, supporting sustainable and safe manufacturing practices.

Professional Applications & Engineering Value

These 4-40 UNC zinc-plated steel rounded head screws are engineered to address common industrial challenges such as corrosion, vibration loosening, and assembly efficiency. The zinc plating provides a protective barrier against rust and chemical exposure, making them ideal for outdoor equipment, electrical enclosures, and automotive components. With a coarse thread and Class 2A fit, they offer rapid installation and secure fastening in soft materials like plastics or sheet metal, reducing the risk of cross-threading. The fully threaded design ensures uniform stress distribution, while the Phillips/Slotted drive accommodates multiple tool types for flexibility in tight spaces. Certified to ASME B18.6.3, these screws deliver consistent performance in high-volume production lines, minimizing downtime and maintenance costs.

Specification Summary & Compliance

This product adheres to precise dimensional standards, including a Class 2A thread fit for reliable assembly and UNC coarse threads with a 4-40 size. Manufacturing conforms to ASME B18.6.3 specifications, ensuring uniformity and strength. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations confirms the absence of hazardous substances, supporting environmental and workplace safety in global supply chains.