S-91241A422 4-40 x 5/8" ASME B18.13 Stainless Steel Pan Head Phillips Screws with Spring Lock Washer

Key Features & Benefits at a Glance

• Enhanced Vibration Resistance – Integrated spring lock washer maintains consistent clamping force under dynamic loads, preventing loosening in high-vibration industrial applications
• Superior Corrosion Protection – 18-8 stainless steel construction with passivated finish provides excellent resistance to rust and chemical degradation in harsh environments
• Optimized Drive Engagement – No. 1 Phillips drive design ensures secure tool engagement and reduces cam-out risk during high-torque installation
• Maximum Thread Engagement – Fully threaded UNC coarse thread configuration delivers superior holding power across the entire 5/8" length
• Reliable Mechanical Performance – 70,000 psi tensile strength and Rockwell B80 hardness ensure structural integrity under demanding load conditions
• Streamlined Assembly Process – Pre-assembled spring lock washer eliminates separate component handling, reducing installation time and inventory complexity
• Industry-Standard Compliance – Meets ASME B18.13 specifications with RoHS 3 and REACH compliance for global regulatory acceptance

Professional Applications & Engineering Value

These 4-40 UNC rounded head Phillips screws with integrated spring lock washers address critical vibration-induced fastener failure in industrial equipment, electronic enclosures, and machinery assemblies. The 18-8 stainless steel core material, enhanced by passivated finish, provides exceptional corrosion resistance for applications exposed to moisture, chemicals, or outdoor elements. The coarse thread design ensures rapid installation in various materials while maintaining Class 2A thread fit precision. The combination of 70,000 psi tensile strength and Rockwell B80 hardness delivers reliable performance in high-stress applications, while the pre-assembled 410 stainless steel spring lock washer eliminates the need for separate locking components, streamlining assembly processes in manufacturing and maintenance operations.

Specification Summary & Compliance

Manufactured to ASME B18.13 specifications with Class 2A thread fit tolerance for consistent mating with standard nuts and threaded holes. The UNC coarse thread (4-40) provides optimal engagement in various materials. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations ensures environmental responsibility and global market acceptance. The complete assembly features passivated 18-8 stainless steel screw body and 410 stainless steel spring lock washer for uniform corrosion protection.