A faceplate is perhaps the most secure method of holding cross-grain items in the lathe. Many turners use a screw chuck, which is a single-screw faceplate, for small items because it is so quick and easy. I use them for many of my smaller bowls.
A screw is often supplied with ordinary chucks so they can be used as screw chucks. But the screw is usually large. The wood needs a large pilot hole and there is a risk of splitting if the wood is small. It can be difficult to screw the blank on and the finished item off the chuck. It’s useful to have a smaller screw chuck, or several in different sizes. If you have an ordinary four-jaw chuck, you can easily make a wooden screw chuck to use with it.
Turn the chuck body
Put a bit of strong hardwood between centres and turn one end to fit the chuck jaws. I use a Vicmarc chuck with ‘shark’ jaws and leave the wood as a plain cylinder. I think long jaws with a parallel grip are best for the job as they give good support to the wood. If you use dovetail jaws, turn a spigot to suit. Make the spigot the best size and shape for the chuck, for a durable, firm grip.
Put the body of the screw chuck in the lathe chuck. Turn the projecting part to the finished diameter. Face off the end, leaving it slightly concave. Mark the centre with the point of a skew chisel and drill an axial pilot hole right through. Make the hole the right ‘tapping’ size for a reasonably stout wood screw. You could do this in the lathe or with a drill press. Countersink the hole to accommodate the lifted grain that you get when inserting a screw into wood. This makes sure the workpiece can bottom out properly when screwed on.
Fit the screw
Choose a screw with a threaded portion longer than the screw chuck body and insert it from the back. Screw it right through until the point protrudes the right distance, say about 20 mm, from the front. The embedded part of the screw should be longer than the protruding part. Otherwise it may turn when screwing items on and off. Apply a drop of superglue to lock the screw in the chuck if necessary. It helps to wax the protruding thread to make it easier to unscrew the workpiece. Cut off the head of the screw that is left sticking out of the back if necessary, and the job is done. For some jobs you might use a bolt instead of a wood screw.
You might find that the screw becomes loose in the chuck, so it turns with the workpiece. Superglue may be enough to stop this, and it is less likely to happen if there is plenty of thread within the chuck, and less in the workpiece. But it can be a nuisance. You can fix the screw in the chuck more securely by welding a washer to the screw, with a couple of holes drilled for small wood screws that stop it rotating. Another method, if you used a slotted screw head, is to tap in small nails and bend them into the slot. A third method is to drill a cross hole at the head of the screw and put a nail through it, inset into a recess in the chuck.
Using the homemade screw chuck
When using any screw chuck, it is important that the screw pulls the workpiece firmly against the outer edge of the chuck face. If this is not achieved, there will be movement and the screw may break. The chuck face, not the screw itself, supports and drives the work. Don’t put big items on a small wooden chuck that is not strong enough to support them safely. Remember that screws don’t hold as well in end grain as in side grain.