S-90317A573 M4 x 8 mm ASME B18.13.1M Stainless Steel Pan Head Phillips Screws with External-Tooth Lock Washer

Key Features & Benefits at a Glance

• Superior Vibration Resistance: Integrated external-tooth lock washer in 410 stainless steel prevents loosening under dynamic loads, ensuring long-term joint integrity in high-stress environments.
• Excellent Corrosion Resistance: Made from 18-8 stainless steel with a passivated finish, offering reliable performance in humid, chemical, or outdoor industrial settings.
• High Tensile Strength & Durability: With 70,000 psi tensile strength and Rockwell B70 hardness, this screw withstands heavy mechanical stresses without deformation or failure.
• Secure & Efficient Installation: Phillips No. 2 drive and pan head design provide easy tool engagement and a low-profile, flush finish for streamlined assembly processes.
• Precision Thread Fit: Class 6g coarse threads ensure consistent, reliable fastening with standard M4 nuts and tapped holes, reducing the risk of cross-threading.
• Full Thread Engagement: Fully threaded design maximizes grip length and load distribution, enhancing holding power across the entire fastener length.
• Regulatory Compliance & Quality Assurance: Meets ASME B18.13.1M standards and is RoHS 3 and REACH compliant, ensuring safety and environmental responsibility in global supply chains.

Professional Applications & Engineering Value

This M4 pan head screw with an external-tooth lock washer is engineered to address critical challenges in industrial assembly, such as vibration-induced loosening and corrosion in demanding environments. The combination of 18-8 stainless steel and a passivated finish provides exceptional resistance to rust and chemical exposure, making it ideal for machinery, automotive components, and electronic enclosures. The coarse metric thread (M4 x 0.7mm) and Class 6g fit ensure quick, accurate installation with standard tools, reducing assembly time and minimizing the risk of thread damage. Fully threaded for uniform stress distribution, this screw delivers reliable locking performance in applications where stability and durability are paramount, from conveyor systems to control panels.

Specification Summary & Compliance

This screw features an M4 x 0.7mm coarse metric thread with a Class 6g tolerance for precise fit, an 8mm length, and a pan head with Phillips No. 2 drive. The external-tooth lock washer (7.87mm OD, 0.6mm thick) is made from 410 stainless steel with a passivated finish. It complies with ASME B18.13.1M manufacturing specifications and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulatory requirements, ensuring environmental safety and industry-standard quality.