Value Collection SEW7X0400-100BX M4 Lock Washer 100pk

Product Description

The VALUE COLLECTION SEW7X0400-100BX is an M4 external tooth lock washer designed to maintain fastener tension under vibration and dynamic loading. It features a 4.3mm inside diameter and an 8.0mm outside diameter, with a 0.5mm thickness. Constructed from Grade 18-8 Austenitic A2 stainless steel with an uncoated finish, this washer delivers solid corrosion resistance in wet, chemical-exposed, or outdoor service environments. Sold in a minimum order quantity of 100 pieces, it is a standard fastener component used across plumbing, electrical, HVAC, and general mechanical assembly applications.

This lock washer is suited for use wherever M4 fasteners require anti-loosening retention in light-duty assemblies. The external tooth profile bites into both the fastener head and the mating surface, creating mechanical resistance against rotation. Typical applications include panel mounting, equipment enclosures, pipe support bracketing, and control box assembly. The 18-8 stainless steel construction makes it appropriate for installations exposed to moisture or mild corrosives, including marine-adjacent and outdoor mechanical systems.

Key Features

• External tooth design bites into fastener head and substrate to resist loosening under vibration
• 4.3mm inside diameter sized for M4 screws and bolts
• 8.0mm outside diameter with 0.5mm thickness for low-profile fitment
• Grade 18-8 Austenitic A2 stainless steel for corrosion resistance in wet and outdoor environments
• Uncoated finish — no plating to flake or react with stainless fasteners
• Sold in quantities of 100 for bench stock and service inventory

Compatibility

Designed for use with M4-threaded fasteners in standard mechanical and trade assembly applications where an external tooth lock washer is specified.

Installation Notes

Install between the fastener head and the mating surface with the teeth facing the fastener head. Ensure the mating surface is clean and free of debris so the teeth can seat properly. Do not reuse lock washers that have been fully compressed, as the tooth profile loses retention effectiveness. This fastener hardware is typically installed by electricians, HVAC technicians, plumbers, or general mechanical contractors during equipment assembly or panel mounting work.