Sidebilder
PDF
ePub

PLAIN TURNING IN WOOD AND IVORY.

To those of our young readers who have a mechanical turn there are few, if any, of the various indoor amusements which can be compared with Turning, and there are none, we are convinced, from which such truly satisfactory results will follow.

Very little real instruction, however, can be imparted by any written directions, however clearly and concisely they may be given, unless they are accompanied by practical demonstration and the actual manipulation of the lathe by a practised performer. The endless variety of patterns and figures which are capable of being produced in the lathe does away with all monotony, and when once the rudiments of the art are acquired the pupil will find himself amply repaid for all the trouble he may have bestowed upon it. He must, however, possess taste in the arrangement of his patterns, in their proportions and in their designs: in the absence of these, all his labour will be fruitless, however great may be the proficiency to which he may attain in the actual working of his lathe.

The first step to be taken is to secure a good lathe; that is, as soon as the pupil finds, by working at the lathe of some professional turner, that he really likes it and can handle the ordinary tools in a tolerably workmanlike manner.

We will suppose that the beginner has obtained the advantage of watching a professional turner at work, and has learned practically the use of the different sized "gouges," and can turn some rude patterns, such as the leg of a chair, with a tolerable amount of finish and without chipping the wood or notching the tools. Let him then be taught and practise the use of the different sized chisels and the point-tools, and this learned properly and their manipulation well understood, the groundwork of plain turmng may be said to bi overcome. The next step we would recommend being taken is that of making a small urn or egg-cup. To do this, proceed as follows:

Having fixed the piece of wood in the chuck (the receptacle, whether of brass or wood, which screws on to the mandril of the lathe), commence turning it with a moderate sized gouge into the rough shape you require; then, with a small " side-tool," hollow out the inside of the requisite size, and finish off with sand-paper. When the inside is completed, turn down the outside to the desired shape, and finish off with sand-paper. After a little practice this will be found to be tolerably easy of accomplishment, and another step in advance may now be taken, viz., that of making an ordinary box. Having selected a piece of wood of the size you require, and fixed it, as before, in the chuck, " rough " it out to the shape you wish, and very carefully turn down the projection to receive the lid of the proper size, and, having finished off this part of the box, hollow it out by means of the side-tool, as before; then chuck the piece of wood intended for the lid, and proceed in precisely the same way, taking care to fit the two very nicely; and, having shut one within the other, finish them off together; then, in order to complete the bottom and top, chuck them the reverse way, removing them, of course, from the original chuck and fitting them to a fresh one.

Then, we would point out the absolute necessity of learning to " chuck " well, i.e., to fix the wood or other material you are about to turn firmly and properly in the chuck. This is a most material and, indeed, indispensable ingredient in the art of turning, and more disappointment and annoyance proceeds from a neglect of this precaution than from any other cause.

The making of a set of chessmen affords most excellent practice to the beginner in more ways than one; it teaches the use of the gouges of various sizes, and of the point-tool and chisels, and, what is of equal importance, turning to measurement, for there must be sixteen pawns all exactly alike and of the same size, four castles, four bishops, two kings, and two queens, and the bases of the knights (the heads, of course, cannot be made in the lathe).

Turning in soft wood is but little practised by the amateur turner, as there is but small scope for the exercise of his ingenuity and taste, besides which the method of turning it is entirely different, the level of the rest upon which the tool is held being fixed far above the centre of the wood which is being turned; while in hard wood and ivory turning it is fixed as much below it, soft wood requiring to revolve directly against the edge of the tool, hard wood at an angle. Besides which, soft wood is not capable of being ornamented by means of the slide-rest and overhead motion, while hard wood and ivory are the best materials for receiving the most delicate patterns.

The best and, indeed, the only woods that will repay the trouble of turning are box-wood, crocus, and the African black-wood. Ebony should under all circumstances be avoided, for, although it is susceptible of taking the most beautiful polish, it is very treacherous, for after, perhaps, hours of trouble and work have been bestowed upon it, it will be found they have been entirely thrown away, a crack appearing and branching in various directions. No material with which we are acquainted can be compared with ivory, the only drawback being its cost; and, on this account, in hollowing it, in making a box, the inside, instead of being cut out in shavings, should always be taken out in rings, by means of a bent-tool and fine parting-tool; and thus much of the material is saved, which is always useful for making rims for pedestals, candlesticks, Sec

It will scarcely be believed by those unacquainted with the working of the lathe that there is no regular shape that is not capable of being produced by means of it, and it is perfectly marvellous what may be performed by common or hand turning. We remember seeing what we consider to have been the most wonderful piece of work ever produced. It was in the Exhibition in Hyde Park in 1851. It was the size and shape of an ordinary hen's egg, and the whole of the inside had been turned out through an opening at one end of only one-tenth of an inch in diameter! It was performed by a journeyman turner in an ordinary lathe. It should be added that the shell thus produced weighed less by some grains than an ordinary egg-shell of the same size.

Tedious as the operation is, nothing in the art of turning repays the trouble and time bestowed upon it more than constantly sharpening the tools and keeping a sharp edge continually upon them, for without this precaution an even surface on the work can never be produced.

Nothing gives so delightful a finish to the smooth surface of the wood as French polish, which may be applied in the lathe. Simple as it may appear, it is by no means an easy matter, and requires a great deal of practice. A piece of hard wood must be turned, and made as smooth as possible with sandpaper, then take a piece of flannel about four or five inches square, and double it, then apply it to the neck of the bottle of French polish, which must be inverted two or three times until a piece of the surface of the flannel, about the size of a shilling, is saturated with the polish, then apply a few drops of salad oil and rub it over it with the finger; the lathe should then be set in motion rather quickly, and as the work revolves the polish should be applied to it evenly and with a very slight pressure, which should be gradually increased as the polish hardens. A second and even a third coat may be given; but great care should be taken not to press too hard against the work, or the friction will burn it and cause dark dull streaks to appear on the face of it. This kind of polish should never be applied to ivory, the best way of polishing which is as follows:

Having finished the work with very sharp tools and the finest "glass-cloth" or sand-paper, mix about a couple of table-spoonsful of common whitening, reduced to a fine powder, with water, until it is of the consistency of cream, and thoroughly saturating a piece of flannel with it, apply it as described above to the work as it revolves, taking care to keep it perfectly wet. When the requisite polish is obtained, a soft brush with dry powdered whitening should be used, and then a piece of flannel soaked in a little salad oil, and, lastly, a silk handkerchief.

In making boxes of hard wood, it is better to rough them out and keep them in a dry place for some weeks before they are used, as sometimes the wood will crack if it happens to be at all damp, which is often the case if it be used directly it is purchased. If hard wood be purchased in any quantity, it is a good plan to glue pieces of brown paper over each end of the log: this will prevent its cracking. Oiling it is also a good plan.

Rhinoceros horn makes a most beautiful material when turned and polished; but the operation is most tedious, for, with every care, it dulls the edges of the tools directly they are applied to it, and the hone must be kept in constant use. After being turned and made perfectly smooth with the finest glass-cloth, it must be polished with a mixture of rotten-stone and oil while revolving in the lathe, as before described.

A few hours' occasional instruction at the hands of a professional turner will do more for a beginner than reading volumes of printed directions; at the same time we feel assured that the few hints we have given will be of essential service.

ORNAMENTAL TURNING.

We now come to the most difficult part of our subject, viz., Ornamental Turning—so called to distinguish it from Common or Hand Turning, as described in our previous article; for by it the most delicate and intricate patterns may be cut on hard wood and ivory with the most delightful accuracy and with mathematical truth, which could not by any possibility be produced without its aid; and as the apparatus necessary for its accomplishment is only an addition to the ordinary lathe, its different parts may be purchased by degrees as the learner gradually attains proficiency.

We will first, then, describe the lathe itself as shown in the annexed woodcut.

A A is a framework of wood, generally mahogany, very strongly and substantially made, on which the other parts of the lathe are put on and taken off as required. In some lathes the "bed" (the horizontal cross-piece at the top and front) is entirely of iron; but this we object to, for we have found by experience that there is much more vibration than there is if it be made only Fig. 1.

[graphic]

partly of that material: and for this reason we recommend that the lower part of it be made of the best mahogany, having two bars of planed cast iron exactly parallel to each other on its top, and half at inch thick, which can be easily added to any lathe having its "bed" formed entirely of wood, which is the case with all low-priced ones.

B is the driving-wheel, which is set in motion by the treadle, c. This should be of cast iron, and the heavier the better. The smaller wheel attached to it (as shown in the drawing) is used in metal turning only, as very much less speed is required than in turning wood or ivory.

D is the " pulley,'' as it is called, over which the catgut band from the driving-wheel passes and sets it in motion.

E is the mandril, having a screw at its end which fits all the thucks, and on which they are screwed as required. It should fit the "head" of the lathe with the most scrupulous accuracy, and should be hollow from end to end (z>., if the lathe has a screw-cutting apparatus belonging to it), as it enables the performer to chuck long pieces of thin wood, ivory, &o, and to turn their ends by passing them through it as well as through the chuck.

F is what is called the " back poppit," and is a movable contrivance attached to the lathe, having a piece of pointed steel, which is capable of being advanced or withdrawn by means of the screw at its rear. It is used when turning any long piece of wood, or other material, in order to keep it steady. It slides between the two iron bearers on the bed of the lathe as before described, and can be fixed at any spot upon them by its binding-screw, as shown in the drawing: the pointed piece of steel which is pressed against the material should be exactly opposite the centre of the end of the mandril.

G is a most ingenious and useful addition to the lathe, as it enables the turner to make screws, whether of the coarser or finer threads, with the most unerring accuracy. It is a plate of brass, three-eighths of an inch in thickness, attached to the end of the head of the lathe, immediately below the end of the mandril, which projects about two and a half inches; and moving on an eccentric, so that it is capable of the very finest adjustment, in order to fit a coarse or fine thread. It is in the shape shown in the engraving.

Six segments of a circle are cut out from its edge. In No. i is cut a coarse thread; in No. 2, a finer one, and so on to No. 6, corresponding with and fitting the six different sized screw-tools. The end of the mandril has a steel cap fitted to it, which is kept in its place by a screw at one end, while the other meets the head of the lathe, and keeps the mandril from advancing when the lathe is at work. There are also six blocks of steel, an inch and a half in diameter and an inch thick, and round FlG a> xmy,,^vmvc. Apparatus. these are cut threads Nos. I and 6, as

before described; these are called " screw guides," and are used in this way: when it is desired to cut a screw (whether coarse or fine), the number is selected, the screw at the end of the mandril must be taken out, the cap removed, and one of the guides put in its place (the guides have holes through them, fitting the end of the mandril), and fixed by the screw. The brass plate must then be moved up and down by means of the eccentric attached to it until the corresponding screw fits into the thread of the guide, and allows

[graphic]
« ForrigeFortsett »