S-90403A540 1/4"-20 x 3/4" ASME B18.13 Steel Pan Head Phillips Screws with Internal-Tooth Lock Washer

Key Features & Benefits at a Glance

• Superior vibration resistance with an integrated internal-tooth lock washer that maintains clamping force under dynamic loads
• Enhanced corrosion protection through zinc-plated steel construction for extended service life in industrial environments
• High-strength performance delivering 60,000 psi tensile strength and Rockwell B69 hardness for demanding applications
• Quick installation with Phillips No. 3 drive and coarse UNC threads that reduce assembly time and prevent cross-threading
• Reliable thread engagement through Class 2A thread fit ensuring consistent performance and easy installation
• Optimal load distribution from the rounded pan head design that minimizes surface damage during tightening
• Regulatory compliance meeting ASME B18.13 specifications while being RoHS 3 and REACH compliant for global applications

Professional Applications & Engineering Value

This zinc-plated steel rounded head screw with integrated internal-tooth lock washer addresses critical vibration-induced loosening in industrial machinery, electrical enclosures, and automotive assemblies. The combination of fully threaded UNC coarse threads and Class 2A thread fit ensures rapid installation while maintaining precise tolerance control. The Phillips No. 3 drive provides sufficient torque transmission for secure fastening without specialized tools. Engineered with 60,000 psi tensile strength, this fastener maintains integrity under heavy loads while the zinc plating offers essential corrosion resistance for harsh operating environments. The rounded pan head profile distributes clamping force evenly, preventing damage to sensitive surfaces and ensuring reliable performance in vibration-prone applications where maintaining joint integrity is paramount.

Specification Summary & Compliance

This 1/4"-20 x 3/4" screw features UNC coarse threads with Class 2A thread fit for consistent dimensional accuracy. Manufactured to ASME B18.13 specifications, the fastener ensures reliable performance in industrial applications. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, meeting international environmental and safety standards for industrial components.