What is Three Jaw Chuck & How Does It Work | Lathe Chuck Types | CNCLATHING


A chuck mounted on the lathe spindle is an essential part of the turning operation, functions as a clamping device to hold the workpiece securely and safely. With many types of lathe chucks, the material to be turned can retain stable and be cut accurately. Among the commonly used jawed chucks, we’ll talk about the three jaw chuck and the difference between 3 jaw chuck and 4 jaw chuck.

What is Three Jaw Chuck?

A chuck is a type of clamp used to hold an object in a specific position, widely used in the CNC machining factory, in drilling and milling, chucks hold the rotating tools, while in turning process, various lathe chuck types are used for fixing the workpiece. Many chucks have jaws that are tightened up to hold the tool or part. Machinists understand the term “three-jaw chuck” as a self-centering three-jaw chuck, also refers to universal chuck, this type is best suited to grip round and hexagonal pieces when requiring very fast, reasonably accurate centering.

How Does a 3 Jaw Chuck Work?

Three-jaw chucks are often used on lathe machines and indexing heads. All of the jaws of three-jaw chucks are fitted into a scroll plate, which makes the 3 jaws can move simultaneously when adjusted by the chuck wrench, then grasps the lathe part very quickly and accurately. The jaws can be made in different sizes. What is a chuck key used for? A chuck key or wrench is a tool designed to tighten or loosen the jaws of the chuck.

Difference Between 3 Jaw Chuck and 4 Jaw Chuck

The most commonly used lathe chuck including 3-jaw and 4-jaw. What’s the difference between the four jaw chuck and three jaw chuck?

1.Construction and motion

Three jaw chuck refers to self-centering chuck, its jaws are interconnected via a scroll gear and move at the same time, while jaws on four-jaw chucks move independently and require operators to center the workpiece.

2. Uses

Three-jaw chuck is the best option for holding circular or hexagonal cross-sections, while 4 jaw chuck is primarily useful for gripping square or octagon block. 

3. Setting time

Four jaw chucks often take longer to set up but can do more than a 3 jaw chuck.

4. Accuracy

3-jaw chuck with an accuracy level of around 0.010 and the accuracy level of 4-jaw chuck is between 0 and 0.001.

5. Number of holes

The three jaw chuck has only one hole for the chuck wrench or key to tighten or release the gripping, but a four jaw chuck has four holes for controlling each jaw, one at a time. 

6. Depth of cut

In four-jaw chuck, the produced depth of cut is higher than that in three jaw chucks.

7. Workpiece weight

Heavier stock can be turned in 4 jaw chuck but can’t in three-jaw.

8. Gripping power

The gripping power of four jaw chuck is larger than 3 jaws.

9. Function

Eccentric turning is possible when the part is fixed in 4 jaw chuck, which can’t be done in 3 jaw chuck. 

Lathe Chuck Types - What are the Different Types of Lathe Chucks

– Jawed chuck (Three jaws universal chuck & Four jaws independent chuck)

– Collet chuck: attached to the spindle by a nut, used for holding bar stock when manufacturing machining parts require quick setting and accurate centering.

– Drill chuck: a specialized self-centering, three-jaw chuck, usually with a capacity of 0.5 in (13 mm) or less and used to hold drill bits or other rotary tools.

– Magnetic chuck: hold magnetic materials with the magnetic flux radiating either from the electromagnets or the permanent magnets, or where the pressure of jaws will cause distortion of the workpiece.

– Combination chuck: used both as self-centering and independent chuck.

– Air operated chuck