10. Woodscrew chuck

Small bowls - Egg cups - Drawer knobs

One of the most useful attachments the woodturner can have for the lathe is the woodscrew chuck. This consists of a small faceplate, between 1 1/2in. and 21/2 in. in diameter, which is screwed on to the mandrel. In the centre an ordinary woodscrew is fixed, either being welded into position or held by a special clamping device, which allows for the screw to be easily adjusted for length and changed if it becomes damaged. This type of chuck is indispensable for turning small parts such as door knobs, egg cups and small bowls, although with care in turning, bowls of up to 12 in. in diameter can be turned quite safely, using this chuck. Woodscrew chucks of 21/2 in. diameter usually have two or three holes drilled in them, so that the work can be held more securely by additional woodscrews.

Now let us put the woodscrew to use and make an egg cup. This is perhaps, the first project the beginner will wish to make, to prove to his wife that he is not just wasting his time. First of all, cut a block of wood 21/2in. square and 4 in. long, the grain running lengthwise down the wood; make sure the ends are cut perfectly square. Draw pencil lines from corner to corner at one end of the wood to find the correct centre. At the centre drill a hole about 1/16 in. diameter and 3/4 in. deep, then screw the work on to the woodscrew chuck. Bring up the tool rest to the correct height, that is, level with the centre line of the work, and as close to the work as possible. Turning the lathe by hand, check that the work will not foul the tool rest. For additional support of the work in the roughing out stage, the tailstock can be brought up to support the other end of the wood, although this is not absolutely essential. The lathe is then started under power to turn the work at about, 2,000 r.p.m. Using a 5/8 in. half round gouge, round off the work as described in turning between centres; turn to a true cylinder, although at this stage it is not necessary to obtain a smooth finish. The next step is to hollow out the egg cup, and several methods can be employed. The easiest is first of all to drill a hole about 1/2 in. in diameter, to the depth of the inside of the cup at the tailstock end of the work. If your lathe has a tailstock fitted with a No. 1 or 2 Morse taper, use a normal three-jaw chuck mounted in it. The 1/2in. hole can then be easily bored with the lathe rotating and advancing the tail-stock into the work, boring to the depth required. If you plan to make many egg cups cut a piece of cardboard to the shape of the inside of the cup, making sure that it is the size of a hen's egg and not a pigeon's! There are a lot of egg cup sets on the market today that will not hold the average size egg and we do want our cup to serve its purpose.

Remove the tailstock away from the work and put it out of the way at the other end of the lathe. Bring the tool rest up to the end of the work and at right angles to the lathe bed, the height of the rest being level with the centre line. Remove the centre of the wood, using a parting tool, working on the left hand side of the hole and gradually roughing out the inside to shape. Do not take too heavy a cut, otherwise you will run the risk of forcing the wood off the woodscrew chuck. If there is any tendency to chatter, lower the tool rest slightly. Finish the inside using a round nosed scraping tool, starting in the centre and working to the outside, using a sweeping action with the handle and holding the blade in the same position on the tool rest. Reposition the tool rest so that it is parallel with the work, and with the parting tool make a groove in the wood, about 1 in. from the woodscrew chuck end. This will mark the position of the base of the egg cup. The outside can now be turned to shape using a 3/8 in. half round gouge, remembering to turn from the larger diameter portions to the smaller. If the outside shape is to resemble a barrel, you may find it more convenient to use the skew chisel, as this gives a smoother finish.

After sanding and polishing, the egg cup is cut away from the waste stock with the parting tool being used in the normal way, at the marked point near the chuck. When the parting cut is nearly through to the centre of the work, the egg cup should be supported with the left hand, whilst the right hand pushes the parting tool for the final cut.

Serviette rings can be made in a similar manner, the only difference being that the inside of the piece of wood is hollowed out leaving the sides parallel. First of all the out­side is rounded as in the case of the egg cup and a 1/2in. hole bored down the end of the wood. The tool rest is then brought up to the end of the wood and at right angles to the lathe bed and the 1/2 in. hole enlarged to about 1 1/2in. diameter using a parting tool or the point of a skew chisel. The length of the hole should be 1 in. to 11/2in. Measure the actual depth of the hollowed inside and mark the point on the outside of the work. Using a 3/8 in. gouge, shape the outside up to the pencil mark, being careful not to cut the ring off at this stage. Remember that you are turning a hollowed out piece of wood, the walls of which are probably only 1/4in. thick. Sand the ring inside and out and polish the inside only, finally cut away with the corner of a skew chisel, not the parting tool, as this will damage the thin shell of the ring.

You are probably wondering about the polishing of the outside, well, this cannot be done at this stage as the cutting of the ring away from the stock would only damage it. To polish the outside, get another block of wood about 3 or 4 in. long and 2 in. square, mount it on the woodscrew chuck and turn it to a gradual taper which will fit the inside of the serviette ring, so that three-quarters of the ring only, is supported, by the taper. The outside of the serviette ring can now be polished and the edges sanded, if required. Keep this block in a safe place. You will probably need it again sometime.

One big advantage of the woodscrew chuck is that articles can be turned and remounted at a later date for finishing. If a number of similar articles are required, it is a good idea to turn them all separately and remount them later so that they can all be finished simultaneously. Door and drawer knobs are a common item for which the turner is asked and you may wonder which is the best way to tackle these. More often than not you will be given a pattern, but if not, make one out of hardboard. It will be useful in the future.

Mount a block of wood on the screw chuck of suitable size, allowing sufficient length to turn a pin or dowel on the end of the knob, as this is the usual fixing method in a piece of furniture. Round off the block with a suitable size half round gouge, to within 1/8 in. of the finished overall diameter. The end of the block farthest from the screw chuck will be the outside of the knob. Using the parting tool, mark a position on the block of wood to indicate the length of the knob, excluding the fixing pin or dowel, making a cut about 1/2 in. deep. Shape the knob using our much used 3/8 in. half round gouge, although some work may call for a smaller gouge.

You may perhaps be thinking that the 3/8 in. gouge is the only tool I ever use; well, I do use it a lot, as I think it is the easiest tool to use for most jobs, but if you think that you can do better in some places with a skew chisel, go ahead and use it. There are no hard and fast rules in woodturning; a lot of it is a matter of choice.

Having turned the knob to shape with the gouge you can round off the end of the work using a skew chisel as this will give a clean cut on the end grain, the heel of the chisel only being used. Sand and polish while still rotating on the lathe. Taking up the parting tool again shape a portion of the wood between the first parting cut and the screw chuck to form a suitable size pin or dowel. Finally cut away the completed knob, supporting the work with one hand and using the parting tool with the other. With work of this type, never make the pin first as there will be insufficient support for the remainder of the work whilst you are turning.

Small bowls of up to eight or nine inches in diameter can be turned quite satisfactorily on the single screw fixing of the woodscrew chuck and can always be remounted for further finishing if required, as the work will always be mounted centrally. One thing that the turner must be careful about is the hollowing out process. Always make a mental note of the length of the woodscrew fixing or otherwise you will cut the end off it whilst hollowing your bowl and consequently spoil it. If a number 12 screw is used, 1/2 in. or 3/4 in. will be sufficient length to obtain satisfactory fixing for a 9 in. bowl. On the other hand, should you be screwing the chuck into end grain, then a longer length of screw will be required. The modern adjustable woodscrew chuck has the advantage of varying the length of fixing screw.

To make a bowl on the woodscrew chuck, first make a small hole with a bradawl in the centre of one side of a disc of wood. Mount on the chuck and turn the outside to shape, using the method you prefer, with the lathe speed about 1,000 r.p.m. Then with a bradawl supported on the tool rest, make a hole about 1/2 in. deep in the centre of the rotating work: do not go any deeper than this. Sand and polish the outside before stopping the lathe. Remove the block of wood from the lathe and remount on the chuck using the new centre fixing, and shape the inside, but do not forget that woodscrew point hidden in the bottom of the bowl. With care, very much larger bowls can be turned on this type of chuck, but additional fixing screw can be used if preferred.

Whatever items are turned on the woodscrew chuck, always try to arrange your method of working so that the screw fixing hole is not on the face side of the finished work and that it can be removed by some subsequent operation, such as drilling. For example, the lid of a powder bowl could quite well be turned on a screw chuck, but owing to the thickness of the wood in use, it would be impossible to hide the screw fixing hole. In such a case, the hole is bored out to say, 3/8 in., and a small turned knob with a similar size fixing pin fitted in it.

When using the woodscrew chuck for turning heavy or large diameter work, it is a good plan to insert a piece of folded glasspaper between chuck and work to obtain a more positive drive and where possible, use your tools so that the wood is cut and not scraped to shape. Cutting puts less strain on the screw centre.

For long heavy work, such as a wooden vase, I recom­mend that the tailstock be brought up to bear on the end of the wood during the initial shaping of the outside, and kept in this position until the whole of the outside is turned and polished. Let us, then, look at the operations required to turn a vase of about 4 in. in diameter and 10 in. long. The wood is first mounted on the woodscrew chuck in the same manner as in the making of an egg cup, and as this is a rather heavy piece of wood, two or three additional fixing screws could be used, to be on the safe side, although this is not absolutely necessary. The tailstock is brought up to support the other end of the wood and turning commenced using a 3/8 in. half round gouge. After sanding and polishing the outside, a three-jaw chuck is inserted in the tailstock and a 1 1/2in. hole bored nearly down to the bottom of the vase and about 1 in. from the face of the woodscrew chuck. If the lathe is rotating at about 1,000 r.p.m. you will find it quite easy to bore the hole.

The next step is to enlarge this hole using a parting tool or skew chisel, although I prefer a good old mortice chisel ground to a nice scraping edge. Remember in this hollowing out process you are cutting end grain wood and progress will be slow and plenty of patience is required.

Take out sufficient wood from the inside so that a small glass tumbler will fit quite loosely—simple isn't it?

Another use for the woodscrew chuck is as a holder for other simple wooden chucks. For instance, you may wish to shape small pieces of dowel, and such things are always difficult to hold if you have no suitable adjustable chuck. To make a small counter chuck, all that is necessary is to mount a block of wood on the woodscrew and turn to a cylinder. Then with the parting tool or skew chisel, make a hole in the end of the wood which is slightly tapered in diameter so that the article to be held is a good push fit.

I have several of these counter chucks of differing sizes and find a great deal of use for them.

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