S-90403A077 2-56 x 3/16" ASME B18.13 Steel Pan Head Phillips Screws with Internal-Tooth Lock Washer

Key Features & Benefits at a Glance

• Superior vibration resistance with integrated internal-tooth lock washers that maintain secure fastening in high-motion environments
• Enhanced corrosion protection through zinc-plated steel construction, extending service life in industrial settings
• High tensile strength of 60,000 psi ensures reliable performance under substantial mechanical loads
• Precise Class 2A thread fit guarantees smooth installation and consistent engagement with mating components
• Optimized Phillips No. 1 drive provides efficient torque transfer while reducing cam-out risks during assembly
• Coarse UNC threading enables rapid installation and superior pull-out resistance in various materials
• Rockwell B69 hardness rating delivers excellent durability and resistance to wear over repeated use cycles

Professional Applications & Engineering Value

These zinc-plated steel rounded head screws with internal-tooth lock washers address critical industrial fastening challenges where vibration-induced loosening compromises assembly integrity. The 2-56 UNC coarse thread configuration provides excellent holding power in metal, plastic, and composite materials commonly found in machinery, electrical enclosures, and automotive components. The pan head design with Phillips drive offers a low-profile solution that combines easy installation with reliable clamp force distribution. Engineered to withstand demanding conditions, these fully threaded screws maintain their 60,000 psi tensile strength across temperature variations and dynamic loads, making them ideal for production lines, maintenance operations, and OEM equipment where fastener failure is not an option.

Specification Summary & Compliance

These rounded head screws feature precise Class 2A thread fit per UNC standards with coarse thread spacing for optimal engagement. Manufacturing conforms to ASME B18.13 specifications, ensuring dimensional accuracy and performance reliability. The products are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, containing no restricted substances above threshold limits. The zinc-plated steel construction meets industrial corrosion resistance requirements while maintaining the specified Rockwell B69 hardness and 60,000 psi tensile strength.