How to use a 4 jaw lathe chuck

How to Use A 4 Jaw Lathe Chuck


A 4 jaw lathe Chuck is the kind of chuck that many woodturners use to hold their workpiece of different shapes, from the square and hexagonal to the wound and irregularly shaped workpieces. One of the top benefits of using this type of chuck is that they are precise and highly accurate. This quality makes them the preferable type of chuck for woodturning. To efficiently use the 4 jaw lathe Chuck, you need to know how it works and the steps to take. But before this, let’s find out more about what this 4 jaw chuck is.

What Is A 4 Jaw Chuck Lathe?

A 4 jaw chuck has two types, the independent and self-centering chuck. The self-centering 4 jaw lathe Chuck has jaws that move together when the knurled rings move. It ensures that the workpiece is held tightly in place. However, this type of 4 jaw chuck works best for square and round stocks.

On the other hand, the independent chucks, instead of moving in tandem, are adjustable. It has four independent adjustable jaws, and with it, you get an accurate measurement. It can also hold your piece well and comes with high-end construction. Unlike the self-centering 4 Jaw lathe Chuck that only works well for square and round pieces. This independent chuck can securely hold both your square, round, hexagonal and irregularly shaped stocks. But this is only possible because of the jaws’ specialized independent movements that enable exact tuning. One thing that limits this type of lathe Chuck is that it takes time to set up.

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The Parts of A 4 Jaw Lathe Chuck

The independent 4-jaw chuck has a jaw at its end. Hence, it has four parts. They all work independently of the other. Hence, you can place a workpiece on it and not bother about the rest parts interfering. One thing similar with them is their ability to reverse and hold the workpiece in the lathe. This feature makes the work of turning a workpiece easy. The parts of a 4 jaw lathe Chuck includes:

1.     The Back Plate

Most chucks may not have a backplate. But the 4 jaw lathe chuck does. The backplate lies at the back of the jaw body with an Allen screw on its body. They make it with a steel material with its back designed to suit the spindle nose taper. The backplate comes with a keyway that allows the key on the spindle nose to pass through it.

2.     The Body

The body is probably the most important part of the 4 jaw lathe chick because it holds it all in place. The material used in making the cast-iron is a stell. It does not easily melt when it comes in contact with fire. This part of the 4 jaw lathe chuck has four openings that are far apart at a 90° range. There are four screw shafts attached to its body using a finger pin, and the screw rotates independently with the chuck key attached to it. The body has a hollow with round rings attached to it. These rings are marked using numbers to know their functions.

3.     The Jaws

The jaws are made from quality carbon steel and can slide in the openings on the lathe body. You can reverse the jaws so that they can carry the hollow work. At the back, a square-like thread holds the jaw,. It helps them work well with the operating screw.

4.     Screw Shaft

Like the other parts of the 4 jaw lathe chuck, the screw shaft is made with a high carbon iron material. At the top of the screw-shaft is a square slot that can house the chuck key. Also, when you observe the body, there’s a cut left-hand square thread. In the middle, the finger pins hold the tapered steps. These finger pins do not allow the screw to advance but help the screw rotate.

Advantages of A 4 Jaw Lathe Chuck

Unlike other jaw lathe chucks, the 4 jaw lathe chuck has various benefits that may make woodturning an easy work. Some of the advantages of a 4 jaw lathe chuck include

  • It helps to precisely center your workpiece.
  • A 4 jaw lathe chuck works well for both your square, round, hexagonal, and unusually-shaped workpieces.
  • 4 jaw chucks can hold the round stocks better than other shapes.


How to Use A 4 Jaw Lathe Chuck

Now that we know the essentials of a 4 jaw lathe chuck, you need to know how to use them. Well, not to worry. Here are some easy steps to using your 4-jaw lathe chuck.

1.     Equal Distancing

To use a 4-jaw lathe chuck, you need to first set the distance between the different parts equally. But do this from the outer edge. Completing this step means that you get enough space to insert your piece.

2.     Put in Your Workpiece

After creating an equal space between the parts, slide your piece inside the lathe chuck. Then, tighten the jaws to hold the workpiece in place. However, make sure not to overtighten the jaw because it could damage.

3.     Find A Dial Indicator

When you insert the workpiece, look for a dial indicator because you will need it now. When you get one, place it at the centered-tip of the workpiece.

4.     Locate the Strings

There are two types of strings, the high and low strings. After using the dial to hold the centered tip, rotate the chuck till you see the strings. When you find them, move them to the lowest number, which is zero.

5.     Check for the Top Swing

After finding the strings and moving it to the lowest number, rotate the lathe chuck again and check for the top swing.

6.     Calculate the Numbers

Look for a calculator and divide the top figures by two. Once you get your answer, rotate the chuck to the derived point.

7.     Move the Dial Indicator to Zero.

When you finish calculating the numbers, move the dial indicator to zero. It will help in carefully adjusting the parts.

8.     Adjust the Parts

Now, you would want to adjust the parts. For this process, start by moving the jaw closer to the dial indicator opposite the indicator.

9.     Place the Dial Indicator on Zero

When you adjust the two axes, loosen the parts and keep adjusting them till the dial indicator reaches zero. Check to work that both ends are rotating.

10.  Start All Over

When you’ve completes the steps listed above, the next thing is to repeat the same process on the remaining axes. Make sure that while you perform this process, the chuck rotates and runs perfectly. You will know a perfectly centered chuck when you can easily remove and put back workpieces of the same sizes without needing to adjust it again. If this is not the case, it means that you will have to start the process all over until you correctly get it.