A lathe chuck is a component that is attached to the lathe spindle and which holds the workpiece. There are many different types of lathe chucks, depending on how they are actuated and how they attach to the spindle and hold the workpiece.
But for this post, what we will be looking at primarily is the number of jaws a lathe chuck has. Here’s a high level view.
Two Jaw
Lathe chucks that have two jaws offer a great deal of flexibility because they can be used for concentrically symmetrical workpieces, but also for those that are irregular or not symmetrical because each jaw can be adjusted independently. However, because they have only two jaws, they are not self-centering and must be adjusted manually before using, which takes more time.
Four Jaw
Four jaw lathe chucks are like two jaw chucks in that the jaws can be adjusted independently of each other. This, like two jaw chucks, makes them ideal for irregularly shaped and asymmetrical workpieces, though they can also be used for square and rectangular pieces as well. Like two jaw chucks they must be adjusted manually and are not self-centering, but because there are more points of contact with the workpiece, they offer better accuracy and control over the workpiece.
Three Jaw
Three jaw chucks have three jaws and are generally a type of chuck known as a scroll chuck, which means that the jaws move simultaneously when they are adjusted via a scroll plate, which means that the chuck is also self-centering. While this does eliminate some of the flexibility offered by two and four jaw chucks, it makes them easier and faster to set up. With cylindrical or concentrically symmetrical workpieces, they’re even more effective. However, because the jaws cannot be adjusted independently, they are not ideal for irregular or eccentric workpieces.
Six Jaw
A six jaw chuck is similar to a three jaw chuck in that six jaw chucks are usually also scroll chucks, with jaws that adjust simultaneously through the scroll plate. That gives six jaw chucks the same general advantages as three jaw chucks; they are fast, easy and efficient to set up and adjust and are ideal for square, rectangular, hexagonal and concentrically symmetrical workpieces. They are not good for irregular or eccentric workpieces, however. One other note is that the additional jaws incur more contact points on the workpiece, making six jaw chucks more secure. The additional contact points also even out the force of pressure holding the workpiece, making six jaw chucks more suitable for more delicate and thin-walled workpieces, or for workpieces that can easily be deformed by the jaws of a chuck.
Soft vs. Hard Jaws
Lathe chucks also have either hard or soft jaws, depending on what they will be used for and how.
Soft jaw chucks are usually made of either mild steel or aluminum and can be machined to match a specific workpiece part contour. Once machined to the desired specifications, they offer unmatched concentricity and the best possible grip on the workpiece.
Hard jaw lathe chucks are made of pre-hardened steel, usually have stepped or serrated jaws for better grip, and are good for general-purpose turning and long-lasting, though they cannot be customized to a specific job.
Need a New Lathe Chuck?
Need to replace some lathe chucks for your shop? Get what you need online at TMT Toolbox. They carry a wide range of different machine tools and machine tool accessories and lathe chucks are just a few of them. You can learn more on their website and if you need help finding anything, get in touch with them directly for assistance.
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