S-90403A538 1/4"-20 x 5/8" ASME B18.13 Steel Pan Head Phillips Screws with Internal-Tooth Lock Washer

Key Features & Benefits at a Glance

• Superior vibration resistance through integrated internal-tooth lock washers that maintain secure fastening in high-stress environments
• Exceptional durability with zinc-plated steel construction providing reliable corrosion protection for extended service life
• High tensile strength performance rated at 60,000 psi to withstand heavy loads and mechanical stress
• Optimized installation efficiency with Phillips No. 3 drive and coarse UNC threads for quick assembly and reduced installation time
• Precise thread engagement with Class 2A fit ensuring consistent performance and reliable connections
• Enhanced fastening security through the combination of pan head design and lock washer for superior clamping force
• Industry-standard compliance meeting ASME B18.13 specifications for guaranteed quality and interoperability

Professional Applications & Engineering Value

These zinc-plated steel pan head screws with internal-tooth lock washers are engineered to solve critical vibration-related failures in industrial equipment and machinery. The combination of 60,000 psi tensile strength and Rockwell B69 hardness ensures reliable performance under dynamic loading conditions, while the coarse UNC 1/4"-20 threads provide excellent engagement in various materials. The Phillips drive system allows for efficient installation in assembly line operations, and the integrated locking mechanism prevents loosening in applications subject to constant motion or thermal cycling. Ideal for manufacturing equipment, automotive assemblies, and heavy machinery where vibration resistance and long-term reliability are paramount.

Specification Summary & Compliance

This 1/4"-20 x 5/8" screw features precision UNC coarse threads with Class 2A fit tolerance for consistent performance. Manufactured to ASME B18.13 specifications with fully threaded design and right-hand thread direction. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial applications.