The turner's companion /

by Anonymous

Perhaps the most useful of all the additions to the lathe is this chuck, for by its aid the turner can alter the centre of his work as he pleases, producing a great variety of circular lines of different sizes, and other ornaments, which cannot be attempted without it. The tools are those already described belonging to the slide rest, which latter, when used with this chuck, assumes quite a different character than when employed with the eccentric and universal cutters and the drill. With these three, it merely serves to mark, by aid of its screw, the distance they require to be from the work, and the position in which they are to be placed, but does not assist in the size or form of the patterns to be cut; with the eccentric chuck, however, it is quite different. The rest marks the size of the circles, while the chuck fixes their position. Thus: suppose you wish to cut a circle, or series of circles, not as in the pattern, No. 1, [plate 6], which begin from the centre and gradually enlarge, but like those in No. 3; the slide rest must be set to the proper position, to enable the tool to cut the requisite circle, and then the chuck must be screwed down till the tool arrives opposite the exact place where the pattern is to be worked. With this chuck the over-head frame is no longer used; the brass and fly-wheels being employed together, as in common turning, the chuck having a wheel of its own by which to regulate the patterns. In the annexed plate, fig. 1, is a front view of the eccentric chuck; fig. 2 is the same seen sideways.

A A are two brass plates, with a screw at the back of them, as shown at P, fig. 2; by this screw it fastens on to the mandrel of the lathe like a common chuck. A A are so shaped as to admit of D sliding up and down them, and the four screws enable the slide to be tightened or loosened. Down the middle of the chuck is a screw with a very fine thread; it is turned at either end by the square head, 3, and thus D slides up and down at pleasure, but cannot in any way get out of its proper position, and, above all, can never shake in its bed. E is a brass wheel divided into 120 teeth, upon which the distances are calculated, the same as on the other brass wheel; in the middle of it, F, is a screw, the same in size as that on the mandrel, upon which the chuck that holds the work must be screwed. The wheel, E, has a spring screw, which, by turning back the spring, H, enables you to move the wheel round as many numbers as you wish, and the steel point, K, marks the one you wish to set it at. L is a small wheel with four numbers marked upon it; by setting it at O, the steel screw passes from line to line of the wheel, E, fig. 2; by turning it one line further, it stops at ¼; another line, it stops at ½; and a third, at ⅓; thus enabling you to cut your patterns as fine and delicate as you like.

The square heads, 3 3, are placed at each end of the chuck, so that the plate D can traverse the whole length, and thus enable you to ornament a square or an oblong piece of work; both heads have four numbers marked upon them, by which you regulate the motions of the chuck. For instance, when D D is screwed up level with the black line O, the screw F will be exactly in the centre of the lathe. Now, suppose the tool in the slide rest is set to cut a very small circle, and you wish, having done that one, to cut several others of the same size round it, thus,

you must turn the chuck down one turn by counting the numbers on the square head, No. 3; and having cut one circle in the proper place, count as many numbers on the brass plate, E, as are necessary to make them fit properly. Should you wish to make a second row of circles larger than the first, besides turning down the chuck, you must, to enlarge them, turn the screw of the slide-rest one turn forwards. All the patterns already given for the eccentric cutter can be done equally well with the eccentric chuck, except the border pattern in No. 4, which can only be worked by the cutter. Patience, calculation, and attention will enable you to perform the most beautiful, minute, and intricate patterns with the eccentric chuck; but though I have endeavoured to give many specimens, when printed they only in a slight degree convey an idea of the real beauty of this kind of turning; the depth of the cut will wholly alter the appearance of a pattern, and the same circles cut with another shaped tool present quite a different appearance; in all, however, there is one rule, which must never be forgotten—viz., be very careful to make your wood or ivory perfectly smooth, flat, and even, before attempting to ornament it, or you will be disappointed by finding that your circles are cut deep in one part and are scarcely visible in another; also remember to line it, as directed when treating of the slide-rest, for this gives much effect to the work.

Plate 11.

Pattern 1, [plate 11]. Begin by the shell. Having smoothed and lined your wood, put a double angular tool (No. 4 of the slide-rest tools) into your rest; turn the slide-screw till the tool is exactly in the centre of your work, when, if you move the wheel round, you will find the tool will only cut a dot. The outer circle is the one with which to commence; turn the slide-rest screw forwards ten whole turns, and you will find you have the circle of the proper size. Now approach the tool to the wood, cut the circle carefully at first, till you decide on the proper depth for the cuts; then set your screw guides, and proceed as follows. For the other ten circles, move the eccentric chuck downwards half a turn, and diminish their size by moving the slide-rest screw backwards half a turn, so as to keep the lower part of each circle in the same place. To have a good effect, shells should be well cut up—that is, each circle should be of a sufficient depth for the edge of the cut to meet the former one, and thus efface the lines made in preparing the wood. The rays from the centre are worked with the drill; put a fine round-ended tool, No. 3 of the drill tools, into the drill; place it in the slide rest, stop the fly-wheel, arrange the cords, and set the tool with the screw guides to cut very little at first. By means of the slide-rest screw, push the drill forwards till the tool touches the outer edge of the shell; hold it well up to the work with the lever; make the lathe go very quick, and move the drill on the slide forwards very slowly, by turning the slide-rest wheel round with the key 12 turns FORWARDS, then the same backwards. Move 12 numbers on the eccentric chuck wheel for each of the other middle lines, and cut them as above; then move the slide-rest half a turn forwards to shorten the line, and move 1 number on the eccentric chuck wheel, and cut a line moving the slide-rest 11 turns forwards, by which it will be equally shortened at each end. Move to the other side of the long lines and do the same. The whole pattern is done in this manner, counting one for every line on the eccentric chuck wheel, and gradually shortening them by reducing the turns of the slide rest. For the third pattern, which would look better done in dots than in circles, take away the drill, put back the slide rest tool-box, and take a flat-ended tool; set it to cut a dot about the same size as the circles, just deep enough to efface the under lines, so that each dot will look bright and shining. Having cut one, count 2 on the eccentric chuck wheel for each of the other 60; then screw the chuck downwards 2 turns, so that the next row may be just above those already done; cut five dots, counting 2 numbers for each, then pass over four and cut five more; and so on to the end. The upper circle is worked precisely the same as the lower one. The outer pattern is done like the arc patterns in [plate 12], counting 5 for each arc on the eccentric chuck.

PATTERN 2.

The middle pattern is formed of eight shells, with only four lines in each; but these parts of shells begin at the centre point, not round it, as in the former pattern. Use a double angular tool, screw the tool slide out 10 turns, and the eccentric chuck downwards, till the outer or largest circle just touches the centre; cut one circle, move 15 numbers on the eccentric chuck wheel; cut another, and continue the same till the eight are done; then diminish each as directed for the shell, counting 15 for every circle. The second pattern, of rings one within another, is worked with the same tool; set it to the centre point of the wood, screw it forwards four turns, then screw the chuck downwards until you can cut a circle just above the shells; count 6 numbers on the eccentric chuck wheel for each of the 20: then diminish your circles by turning the slide-rest screw backwards half a turn; do the second row, counting 6 as before, and the same for the two inner ones. A still prettier way of doing this pattern is to cut steps instead of circles. Put a fine flat-ended tool into the slide, set it to cut a circle the same circumference as the largest in the pattern; then reduce its size as before, and cut the next deeper, by screwing out the screw guides a very little; the third is still smaller and deeper. A little dot should remain in the middle, standing up as high as the level of the wood; to do this pattern the wood must be thick, as the steps require a certain depth. The outer pattern is done in the same manner as that in pattern 1, only the numbers are counted differently.