- Tachymetric Scale -
In order to calculate units in an hour, watchmakers will use Tachymetric scales. Generally, this scale will be on the edge of the dial or the bezel of the watch. Watch owners can time themselves while driving to determine how many miles they travel in a predetermined increment of time. Watchmakers also refer to the Tachymetric scales as a tachymeter or tachometer.
- Telemeter Scale -
Calculating distances on a watch is easy when using telemeter scales. Some people use these scales to determine how far away bad weather is from their location. By timing the lightning strikes around you, it will be easy to tell how far off a storm is. Generally, this scale uses the large second hand of a watch to point in the direction of what needs to be timed. Many troops also use this feature to determine how far away enemy gunfire is from their location.
- Tourbillon -
The tourbillon on a watch has a round shape and is designed to turn one time every minute. The oscillation and escapement system is located within the tourbillon. These systems stay in a vertical position due to the shape of the tourbillon and with a little help from gravity. This system is now found in some of the highest quality watches on the market. Due to the complexity of the tourbillon, only experienced watchmakers can make it work correctly.
- Tricompax -
A Tricompax is a term used to describe how three subdials are arranged. Usually, they are in the shape of a V.