S-90403A535 1/4"-20 x 3/8" ASME B18.13 Steel Pan Head Phillips Screws with Internal-Tooth Lock Washer

Key Features & Benefits at a Glance

• Vibration-Resistant Locking: Integrated internal-tooth lock washer prevents loosening under dynamic loads, ensuring reliable performance in high-vibration industrial environments.
• Superior Corrosion Protection: Zinc-plated steel construction offers excellent rust resistance, extending service life in demanding applications.
• High Tensile Strength: 60,000 psi tensile strength and Rockwell B69 hardness provide exceptional load-bearing capacity for secure fastening.
• Easy Installation: Phillips No. 3 drive and standard pan head design enable quick, tool-compatible installation with reduced cam-out risk.
• Wide Compatibility: UNC coarse 1/4"-20 threads with Class 2A fit ensure easy engagement and reliable performance in various materials.
• Full Thread Engagement: Fully threaded design maximizes grip strength and distribution across the entire fastener length.
• Regulatory Compliance: Meets ASME B18.13 specifications and environmental standards including RoHS 3 and REACH for global industrial use.

Professional Applications & Engineering Value

These zinc-plated steel pan head screws with internal-tooth lock washers deliver critical vibration resistance in machinery assembly, automotive components, and electrical enclosures where loosening could cause operational failures. The coarse UNC 1/4"-20 threading provides rapid installation and strong holding power in softer materials or pre-tapped holes, while the Class 2A thread fit maintains precise tolerances for consistent performance. The combination of 60,000 psi tensile strength and Rockwell B69 hardness ensures these fully threaded screws withstand shear and tensile stresses in heavy-duty applications, making them ideal for production lines requiring both speed and reliability in fastening operations.

Specification Summary & Compliance

This 1/4"-20 x 3/8" screw features UNC coarse threads with Class 2A fit for standard industrial applications. Manufactured to ASME B18.13 specifications, it ensures dimensional accuracy and performance reliability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, meeting global standards for hazardous substance restrictions in industrial components.