INT/EXT WASHER

An INT/EXT WASHER is a locking washer with radial teeth formed around both the inner hole and the outer edge. It may also be referred to as an internal-external tooth lock washer. After tightening, the internal and external teeth create multiple points of engagement with the screw, nut, and workpiece surface, increasing frictional resistance and providing auxiliary anti-loosening performance.

Product Name: INT/EXT WASHER / Internal-External Tooth Lock Washer
Product Structure: Radial teeth arranged around both the inner hole and outer edge
Primary Functions: Provides auxiliary anti-loosening, increases friction, and establishes metal-to-metal contact
Applicable Fasteners: Screws, bolts, nuts, and mechanical assemblies
Inner Diameter: Selected according to the size of the matching screw or bolt
Outside Diameter: Standard dimensions or as specified by drawing
Number and Profile of Teeth: Manufactured according to size, contact surface, and engagement requirements
Materials: Spring steel, carbon steel, stainless steel, or other specified materials
Heat Treatment: Can be evaluated according to hardness, elasticity, and fatigue-resistance requirements
Surface Treatments: Zinc plating, nickel plating, black oxide, passivation, or other specified finishes
Production Methods: Stamping, forming, and heat treatment
Packaging: Bulk packing, bag packing, or box packing

Multiple Engagement Points on Both Inner and Outer Edges

The internal and external teeth can simultaneously contact the area around the fastener and the workpiece surface, creating multiple engagement points and increasing frictional resistance across the fastening surface.

Provides Auxiliary Anti-Loosening Performance

When compressed, the teeth can bite into the mating surfaces, helping reduce the possibility of reverse rotation of the screw or nut under general vibration conditions.

Provides Elastic Contact Pressure

The internal and external teeth generate spring-back force when compressed, helping maintain contact pressure and compensate for minor surface irregularities or small gaps.

Helps Improve Electrical Grounding

The teeth can penetrate localized paint, oxide layers, or surface coatings to establish metal-to-metal electrical contact, making INT/EXT WASHERS suitable for enclosures and electrical control equipment.

Suitable for Larger Contact Areas

Compared with washers featuring only internal or external teeth, the INT/EXT WASHER provides engagement across a wider range of contact points. It is commonly used in electronic and electrical equipment, machinery, automotive and motorcycle components, and sheet metal assemblies.