A lathe chuck is a type of clamp used to hold the rotating tool bit on a lathe. A lathe chuck is also called a collet, as it is shaped like a collar around the tool base and holds the tool firmly in place. The collet is comprised of two pieces: a cylindrical sleeve or inner surface and a cone shaped outer surface. A collet has shallow cuts along the length to provide space for expansion and contraction as the metal heats up and cools with use.
There are two types of lathe chuck designs: pulled or pushed. In the pulled version, a threaded section is built into the rear of the tool. As it is used, the grooves pull the lathe chuck in tighter. A push design works using a tapered shape and a threaded cap to push the drill bit deeper into a corresponding socket to create the clamp. Both methods use the same design principle. As the lathe chuck is moved toward the socket, it will contract and tighten the grip on item in the inner cylinder.
A lathe chuck is available for both wood and metal lathes. Woodworking lathes in the North America are usually 0.25” (0.63 cm) or 0.50” (1.27 cm) bits. European bits are usual 0.23” (0.63cm) or 0.31” (0.8cm). Metal lathes have a much broader range of sizes and options. The different size chucks determine the drill and tool bits that can be used.
Review the options available for your lathe by reviewing the detail specifications in the product manual. When using a lathe chuck, be sure to follow the safety instructions when changing the tool. If you don't follow the instructions correctly, the bit can begin to move within the chuck, and cut your fingers. Make safety a habit and simply follow the same process every time.
The most commonly used lathe chucks are the three and four jaw models. These models were developed in response to a need for a firmer grip on drilling bits and cutting tools as lathes were used on harder materials. When selecting a jaw model chuck, make sure that you are able to access the components easily to adjust the tool as needed.
In the three jaw chuck, the three jaws are connected with a spiral gear that moves them simultaneously. The outer or inner surface can be used for gripping, providing additional flexibility. The four jaw chuck is very useful if the end product is not exactly centered, or is based on axial symmetry. All four jaws move independently, providing freedom of movement to create different angles.