S-90401A540 1/4"-20 x 3/4" Hex Head Screws with Lock Washer

Key Features & Benefits at a Glance

• Superior vibration resistance with an integrated external-tooth lock washer that maintains tight connections in high-motion environments
• Exceptional tensile strength of 60,000 psi ensures reliable performance under heavy loads and stress conditions
• Enhanced corrosion protection from zinc-plated steel construction, extending service life in industrial settings
• Quick and secure installation with a standard external hex drive and coarse UNC threads for efficient assembly
• Precise thread fit (Class 2A) guarantees consistent engagement and reduces the risk of cross-threading
• Full threading along the 3/4" length provides maximum grip and adjustability in various material thicknesses
• Compliance with RoHS 3 and REACH regulations ensures safe, environmentally responsible use in global markets

Professional Applications & Engineering Value

This zinc-plated steel hex head screw is engineered to address common industrial challenges such as vibration-induced loosening and corrosion. The external-tooth lock washer bites into surfaces to prevent back-off, making it ideal for machinery, automotive assemblies, and structural frameworks where dynamic loads are present. With a Rockwell B70 hardness and 60,000 psi tensile strength, it withstands high-stress applications without compromising integrity. The coarse UNC thread and Class 2A fit facilitate rapid installation in metals and plastics, reducing assembly time while ensuring reliable, long-lasting fastening in demanding environments.

Specification Summary & Compliance

This screw features a 1/4"-20 UNC coarse thread with Class 2A tolerance for precise fit, a 3/4" length, and full threading. It includes an external-tooth lock washer (OD: 0.475", thickness: 0.028") made from zinc-plated steel. The product conforms to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring adherence to environmental and safety standards for industrial use.