S-90402A546 1/4"-20 x 7/8" ASME B18.13 Steel Pan Head Phillips Screws with External-Tooth Lock Washer

Key Features & Benefits at a Glance

• Superior vibration resistance with integrated external-tooth lock washer that maintains clamping force under dynamic loads
• Enhanced corrosion protection through zinc-plated steel construction for extended service life in harsh environments
• High-strength performance with 60,000 psi tensile strength and Rockwell B69 hardness for demanding applications
• Reliable thread engagement through UNC coarse threads with Class 2A fit for quick assembly and secure fastening
• Optimized drive transfer with Phillips No. 3 drive that prevents cam-out during installation
• Full-threaded design provides maximum grip length and uniform stress distribution along the entire fastener
• Regulatory compliance meets industry standards including ASME B18.13, RoHS 3, and REACH for global acceptance

Professional Applications & Engineering Value

These zinc-plated steel rounded head screws with integrated external-tooth lock washers deliver exceptional engineering value in vibration-prone industrial environments. The combination of UNC coarse threading and Class 2A thread fit ensures rapid installation while maintaining precise tolerances critical for manufacturing equipment, machinery assembly, and structural frameworks. The fully threaded design maximizes surface contact area, distributing clamping forces evenly to prevent joint failure. The zinc-plated finish provides reliable corrosion resistance, making these Phillips drive screws ideal for outdoor equipment, automotive components, and industrial machinery where environmental factors threaten fastener integrity. The external-tooth lock washer bites into both the fastener head and mounting surface, creating a permanent locking action that withstands extreme vibration and thermal cycling.

Specification Summary & Compliance

This 1/4"-20 x 7/8" screw features UNC coarse threads with Class 2A thread fit for standard industrial applications. Manufacturing complies with ASME B18.13 specifications ensuring dimensional accuracy and performance reliability. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental regulations for hazardous substances. The external-tooth lock washer provides secure fastening while the zinc-plated steel construction delivers both corrosion resistance and mechanical strength up to 60,000 psi tensile strength with Rockwell B69 hardness rating.