Chucks are one of the handiest ways of holding work on the lathe. There are a few types of chucks but the most common and versatile are the 4-jaw, self-centering chucks. Let’s talk about things to be aware of in general use and ways of taking advantage of that versatility.
Types of chucks: variations on the theme
In the photo above you will see that chucks are opened and closed in two ways: two “tommy bars” or a single chuck key or chuck wrench. The tommy bar chucks on the right are less expensive but still hold smaller work very well. Keyed chucks are easier to operate because you use one hand to tighten them but more importantly they can be tightened more securely. The jaws move in and out by rotating a “scroll” plate with the tommy bars or through a gear operated by the key.Keyed chucks vary in size, ranging from very small to large, covering most work for the average turner. Very large or irregularly shaped work pieces require a faceplate, held to the work with strong screws, so chucks do have their limitations.
The jaws are able to hold work by clamping externally on a tenon on the work piece, expanding internally into a recess in the work piece or screwing the worm screw into a hole drilled into the work piece. The worm screw is held by the jaws. Be sure to read the manufacturer’s instructions to insert the screw into the chuck properly.
By the way never, never, never leave tommy bars or a chuck wrench in the chuck unless you are actually using them. You haven’t lived until you’ve seen a chuck wrench go through a block wall when the lathe is turned on inadvertently.