S-90276A108 4-40 x 3/8" ASME B18.6.3 Steel Round Head Slotted Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, extending service life in demanding environments.
• Reliable fastening performance ensured by Class 2A thread fit, providing consistent engagement and reducing the risk of cross-threading.
• Enhanced durability from Rockwell B69 hardness, offering excellent resistance to wear and deformation under load.
• Broad compatibility with UNC coarse threading and 4-40 size, making it ideal for a wide range of industrial assemblies.
• Easy installation and removal with a standard slotted drive, allowing for quick maintenance using common tools.
• Full thread coverage along the 3/8" length ensures maximum grip and holding power in various materials.
• Compliance with major standards including ASME B18.6.3, RoHS 3, and REACH, guaranteeing safety and regulatory adherence for global supply chains.

Professional Applications & Engineering Value

This 4-40 UNC zinc-plated steel rounded head slotted screw is engineered to address common industrial challenges such as corrosion, vibration loosening, and assembly efficiency. The zinc plating provides a protective barrier against moisture and chemicals, significantly reducing rust in harsh conditions like outdoor equipment or manufacturing settings. Its coarse UNC threads and Class 2A fit deliver secure fastening in metals and plastics, minimizing the risk of strip-out during high-torque applications. The rounded head design distributes pressure evenly, preventing surface damage, while the slotted drive allows for straightforward installation with standard screwdrivers. Ideal for machinery, electronics, and automotive components, this screw ensures long-term reliability and simplifies maintenance, supporting efficient production lines and reducing downtime.

Specification Summary & Compliance

This screw features precise Class 2A thread fit per UNC standards, ensuring dimensional accuracy for consistent performance. It is manufactured in accordance with ASME B18.6.3 specifications, covering head dimensions, thread form, and mechanical properties. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), it meets environmental and safety regulations, making it suitable for use in restricted substance-sensitive industries. The fully threaded design and right-hand threading provide reliable fastening across various applications.