Value Collection SIW7X1800-050BX M18 Internal Tooth Lock Washer

Product Description

The VALUE COLLECTION SIW7X1800-050BX is a stainless steel internal tooth lock washer designed for M18 screw applications. The internal tooth configuration grips the bearing surface of the fastener head, resisting loosening caused by vibration and torque. Manufactured from Grade 18-8 Austenitic A2 stainless steel, this washer delivers solid corrosion resistance in wet, chemical-exposure, and outdoor environments. The uncoated finish maintains dimensional consistency and is suitable for use where galvanic compatibility with stainless fasteners is required. Electricians, plumbers, HVAC technicians, and mechanical contractors install this type of hardware in equipment assemblies, panel mounts, and structural connections requiring reliable fastener retention.

This washer is sized for M18 fasteners with a 19mm inside diameter and a 30mm outside diameter, placing it in a mid-to-large hardware category suited to industrial and commercial mechanical assemblies. It is appropriate for use in corrosion-prone environments such as rooftop HVAC equipment, pool mechanical rooms, marine-adjacent installations, and stainless fastener assemblies where a coated or zinc-plated washer would introduce dissimilar-metal concerns. The 1.4mm thickness provides adequate spring bite without excessive stack height in close-tolerance assemblies.

Key Features

• Internal tooth design bites into fastener head bearing surface to resist vibration-induced loosening
• Grade 18-8 Austenitic A2 stainless steel construction for corrosion resistance
• Uncoated finish eliminates coating thickness variability and is galvanically compatible with stainless fasteners
• 19mm inside diameter sized for M18 screw applications
• 30mm outside diameter provides broad load distribution on the mating surface
• Does not meet military specifications — suited for commercial and industrial use

Compatibility

Designed as a standard internal tooth lock washer for M18 fastener applications. Confirm inside diameter, outside diameter, and thickness against assembly tolerances before installation.

Installation Notes

Install with the teeth facing the underside of the fastener head, not the mating surface, to allow proper bite during tightening. Power down or de-energize any equipment before performing fastener work in electrical or HVAC panel assemblies. Use appropriate torque procedures per the equipment manufacturer or applicable code; do not overtighten, as excess torque on stainless fasteners can cause galling. Inspect the washer seating surface for burrs or debris prior to assembly.