External Tooth Washer

External tooth lock washers (DIN 6797 Form A) feature outward-facing serrated teeth that bite into the fastener head and substrate, creating a mechanical lock against rotational loosening under vibration.

Specification #

Dimension #

• All dimensions in mm, tolerance +/- 0.01 mm. Additional dimensions available on request.

Benefits #

External tooth lock washers solve the problem of fastener rotation in assemblies exposed to vibration and shock loads. The hardened serrated teeth penetrate both the fastener bearing surface and the mating substrate, creating a dual-surface mechanical lock that resists loosening more effectively than friction-based methods alone. The wider tooth engagement area compared to internal tooth washers delivers stronger locking force. The flexed teeth also absorb vibrational energy, reducing the transmission of dynamic loads into the bolt thread. These washers work effectively with pan head, button head, and binding head screws where the head diameter contacts the teeth. They provide a low-profile locking solution at minimal cost, requiring no special tooling for installation.

Common Applications #

External tooth lock washers are used in assemblies where vibration resistance and a reliable mechanical lock are required without adding significant height to the joint.

• Electrical connections and terminal blocks
• Automotive body panels and trim
• Electronic enclosures and control panels
• Sheet metal assemblies
• Appliance manufacturing
• Machinery with moderate vibration
• Conveyor system components
• General industrial assemblies with pan, button, or binding head screws