An ER collet is a popular type of chuck, which in turn is a clamping system used to hold something in place. If you look at an electric drill, for example, you’ll see that the drill bit itself is held in place by a cylinder. This is the chuck.
A high-quality ER collet does an excellent job when it comes to keeping stuff in place. A drill bit is going to spin at a rapid rate and powerful forces will be exerted onto the drill and drill bit.
Without a collet, the drill bit wouldn’t be held in place.
The ER collet is perhaps the most popular clamping system in the world, often made from alloy spring steel. These collet chucks are often used for boring, milling, grinding, reaming, and other processes.
Well-designed collet chucks will essentially provide gripping force and power all around the drill bit or whatever else is being held in place. This helps to ensure a strong grip and stability.
Collet wrenches are also very useful tools that can provide a tight grip, making them a great choice for working with stubborn nuts and the like. Given how versatile collets are, many people already have them in their toolbox.