What Is the Purpose of a Machined Tooth Washer?

The primary purpose of a machined tooth washer is to increase the locking ability of a fastener assembly by creating a high-friction interface. Unlike plain washers, which only distribute load, tooth washers actively resist rotation. When the washer is compressed under bolt or screw tightening torque, its serrated edges penetrate slightly into the surface of the fastened material. This creates a mechanical interlock that dramatically increases resistance to loosening.

Additionally, tooth washers function as a vibration-control element. The individual teeth flex slightly under dynamic forces, absorbing part of the movement and reducing micro-slippage between the fastener and the substrate. This makes tooth washers especially effective in environments where continuous vibration or thermal cycling is present.

Other key purposes include:

Maintaining long-term preload by preventing rotational back-off

Providing electrical grounding in some metal-to-metal assemblies (due to the teeth penetrating coatings)

Ensuring consistent clamping pressure even when materials expand, contract, or settle

Enhancing long-term joint reliability by combining frictional and mechanical locking

Overall, tooth washers serve as an efficient, low-cost solution to improve fastening integrity, especially in situations where conventional plain washers are insufficient.

Differences Between Internal and External Machined Tooth Washer

Machined Tooth Washers are commonly categorized into two types—internal tooth lock washers and external tooth lock washers. Although they share the same locking principle, their geometry and performance characteristics differ significantly. Understanding these differences helps in choosing the right washer for the intended application.

Machined Tooth washers play a crucial role in ensuring the reliability of bolted connections by combining frictional locking with mechanical interlocking. Their ability to resist loosening, stabilize preload, and enhance joint durability makes them essential in many industrial settings. Understanding the structural differences between internal and external tooth designs enables engineers and users to select the most effective option for their specific application requirements.