Value Collection SEW8X0400-100BX M4 Lock Washer Ss 100pk

Product Description

The VALUE COLLECTION SEW8X0400-100BX is a stainless steel external tooth lock washer sized for M4 fasteners. It features a 4.3mm inside diameter and an 8.0mm outside diameter, with a 0.5mm nominal thickness. The serrated external teeth bite into the mating surface and fastener head to resist loosening from vibration and torque. Manufactured from Grade 18-8 austenitic stainless steel in the A2 classification, this washer provides solid corrosion resistance in wet, outdoor, and chemically exposed environments. Electricians, plumbers, HVAC technicians, and mechanical contractors use external tooth lock washers in panel assemblies, equipment mounting, and general fastening applications where joint integrity must be maintained over time.

This washer is suited for light- to medium-duty fastening applications where an M4 screw or bolt is used. Common use cases include equipment enclosure assembly, electrical panel grounding connections, HVAC unit mounting brackets, and plumbing fixture hardware. The external tooth profile distributes clamping load around the perimeter of the fastener, making it a reliable choice on softer base materials or painted surfaces where a standard flat washer would not provide adequate locking action. Sold in a minimum order quantity of 100 pieces per transaction.

Key Features

• External serrated tooth design bites into fastener and mating surface to resist rotation and loosening
• Grade 18-8 austenitic stainless steel, A2 classification, for corrosion resistance in humid and wet environments
• 4.3mm inside diameter fits M4 screws and bolts with standard clearance
• 0.5mm thickness provides a low-profile locking solution without adding significant stack height
• Sold in quantities of 100 for shop stock, service van inventory, or production use

Compatibility

Designed for use with M4 screws and bolts in general mechanical, electrical, and plumbing fastening assemblies requiring an external tooth lock washer.

Installation Notes

External tooth lock washers are installed between the fastener head and the mating surface or between a nut and the mating surface. Position the washer so the teeth face the fastener head or nut, not the base material, unless the base material is soft enough to accept tooth engagement on both sides. Torque the fastener to the value specified for the M4 thread class and material being joined. In electrical grounding applications, follow NEC requirements for bonding hardware and confirm the washer material is compatible with the conductor and enclosure materials to avoid galvanic issues.