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Now that we have reviewed what a lathe jaw chuck is, let’s take a closer look at the 3 jaw chuck. A 3 jaw chuck is a type of scroll chuck commonly used in woodworking and metalworking. It is so named because it has three jaws. These jaws move simultaneously to hold your wood or metal workpiece.
The 3-jaw chuck is easy to use and very versatile. Also, it is designed to hold cylindrical or irregular shapes securely. It is a very versatile tool that can handle a range of shapes and sizes for various turning projects.
Parts of a 3 jaw chuck
Body
The body is the central part of the chuck. It attaches to the lathe spindle. Need a refresher on the lathe spindle? Head over to our post on parts of a lathe machine.
Jaw
The jaw is made of three moveable components. These three jaws grip and securely hold the workpiece.
Scroll Mechanism
This is the system that moves the jaws. For a 3 chuck jaw, there is usually a screw, handle, or chuck key that is used to turn the mechanism. That then makes all three jaws move in and out in unison.
Types of 3 jaw chucks
Self-centering chucks are the most commonly used type of 3-jaw chuck. That means that as you tighten the jaws to hold your workpiece, the piece is also automatically being centered. This is really convenient when working with round and cylindrical pieces.
While much less common, there are non-self-centering 3-jaw chucks.You’re more likely to see an experienced woodworker or machinist use one when they need more control over the positioning of an irregular workpiece.
For the average wood or metalworker, a self-centering chuck is the way to go.
How to Use a 3-jaw chuck
Mount the chuck
Attach the chuck to the lathe spindle. Usually, the chuck comes with mounting screws. Or, if your lathe is set up for it, you can use a threaded chuck for quick mounting. Check out our post for lathe chuck mounting methods.
Insert the wood or metal
Open the jaws bigger than your piece of wood or metal and insert your workpiece.
Adjust the jaws
Use the scroll mechanism to tighten the jaws around the piece of wood or metal. The jaws will move together to grip and center your piece in relation to the lathe spindle. A securely mounted and centered workpiece is crucial for accurate turning.
Tips for using a 3 jaw chuck
A lathe does not come with chucks. They are an accessory purchased separately. Once you have your 3-jaw chuck are ready to use it:
Adjust gradually
Turn the scroll mechanism slowly and steadily. This allows the jaws to tighten uniformly around the piece.
Check for proper engagement
The jaws are properly engaged when they grip the workpiece evenly and securely. There should not be any wobbling or shifting. Some wobbling and shifting might not be noticed until the machine is turned on. Especially if you’re a beginner, when you’re ready to start, turn the machine on at a slow speed. Watch how the piece rotates. If there is any wobbling or the piece looks off, stop the lathe machine and make adjustments. If all looks good, gradually increase to the desired speed and get to work.
Verify Centering
After tightening, double-check that the workpiece is centered. Yes, even with self-centering chucks. It should be a real quick double-check. It’s always a good idea to double-check the setup turned out as expected, in case adjustments need to be made, before getting to work.
In summary, a 3-jaw chuck is a practical and efficient tool for holding your workpiece securely and accurately while you turn it. Its ability to center the workpiece automatically and handle different shapes makes it a popular choice for many experienced woodturners and machinists.