Read Ebook: A Manual of the Hand Lathe Comprising Concise Directions for Working Metals of All Kinds Ivory Bone and Precious Woods by Watson Egbert P Egbert Pomeroy

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It is necessary to have as many different hubs, varying in pitch, as there are different kinds of work to be done, and, although the thread on the hub is only an inch or half an inch long, perhaps, a screw of any length may be cut on a rod, by simply shifting the cutter on the rest. This same bar is also useful for turning, as with a slide rest, for, by sliding it along gradually, it acts, in a measure, like a fixed tool in a slide rest.

From these hints the amateur who takes a lathe in hand for the first time, or is, at best, a neophyte, may learn much to his advantage. Persons of a mechanical turn only need a hint, when the mind springs to the conclusion with surprising rapidity.

CHUCKING.

Chucking work in the lathe is one of the most interesting branches, for here there are no centers in the way, to plague the workman, and the tool has a fair sweep at all parts. Every one who uses a lathe, should get a scroll chuck, Fig. 21, of Cushman's make, that is, a chuck where the jaws move up together toward the center, so that any round piece will be held perfectly true. This is a great convenience, for whether we have a ring to bore out, or a wheel to turn off, it is equally handy, and is far better than the independent jaw chuck, which has to be set up by measurement, and repeated trials before it is right. To those who cannot afford to purchase a scroll chuck, a wooden one can be made to answer every purpose. Wooden chucks should be made of some hard, fine-grained wood, such as maple or mahogany, so that they will hold well whatever is driven into them.

If we have a small cylinder head to turn, for instance, the back head, which has no hole in it to put a mandrel through, as the front one has, the wooden chuck will come in play. To make one, the turner takes a square block of the proper thickness, say one inch, and saws the corners off, so that it is eight-sided. It is then ready to screw on the face plate of the lathe. This is quickly done by having small screw holes in the plate for this purpose, as shown in Fig. 1, page 17.

The block is then all ready to work on, and the face must be turned off true, and a recess cut out in it to receive the head. This is the head, Fig. 26.

On the back side, there is a projection to fit the cylinder of the engine. This must be turned first, and the flange faced off true: after that the head must be pryed out, reversed, and put in the chuck again, the finished side in, so as to polish it on the outside. Fig. 27. It must be driven up tight against the face of the chuck, otherwise the flange will be thicker on one side than the other. In finishing, it will be found better to commence near the center, and work out toward the largest diameter, for it is necessary to get under the scale, or sand, left on in casting, first, before the work can be turned true, and this is easiest done by beginning at the middle, where the speed is low. The scale is fused sand melted on the metal in the act of casting. The best tool to do this with is the diamond-point, for it can be employed universally on straight or hollow surfaces, is easily ground, and always works well. After it, comes the scraper, previously shown. If these chatter, a piece of leather must be put between them and the rest. It is also well to put a stout iron rod, or piece of hard wood, between the back center of the lathe and the face of the plate; this keeps everything steady, as shown below, so that a beautiful luster will be given by the tool alone.

After the plate or head is firmly scraped, it must be polished with flour emery and oil. The emery first used must be No. 1, which is about like Indian meal; if the work is brass, however, this will not be needed. This must be plentifully supplied with oil, so that it is like cream, and the workman, taking a soft pine stick, with the end pounded into a brush, so that it will hold emery, holds it hard up against the face of the head. If it has been properly scraped, a few revolutions will produce a fine-grained finish, but if it is badly done, the corners will be full of scratches and chatters. It takes time and experience to make a good finisher, and patience also, for men who are good turners, and can make excellent fits, are sometimes botches at polishing.

After emery of the finest possible description has been used, a little rouge powder should be put on a piece of buckskin and applied to the work. This will make a polish equal to gold on brass, and like silver on iron. Instead of these methods many persons burnish their work. The burnisher is sometimes made of steel, of bloodstone, and of agate. Steel is the material generally employed. It is polished as bright as can be on a buff wheel, and must be preserved so, otherwise it is useless to attempt doing anything with it. Pumice stone is very good for polishing with, or rather for finishing the surface before polishing. Other substances will be mentioned hereafter. Steel and iron are best polished with a sharp tool and water. To turn steel with a handsome surface, the tool must be sharpened on an oil stone, and the speed high, then spit on the work and take light cuts, and you will have a nice job. To make a very brilliant polish on steel, it is necessary to use emery and oil, plenty of oil and not much emery, but this makes such a nasty mess on the lathe, that few good turners will do it. A file should not be used in the lathe if possible; filing a job makes it uneven, and spoils the looks of it. It is difficult to avoid scratches, and the expert can generally tell the difference between work that has been turned true, and that which has been filed, and, in nearly all cases, it is quicker to turn the work to fit or to finish at once.

In polishing round work, such as rods or shafts, it is much cleaner, and more expeditious, to make a pair of clamps like Fig. 28, and put the emery and oil on leather pads between them. The clamps consist of two straight pieces of soft or hard wood, lined with leather, though some use sheet lead.

This discussion about polishing has led us away from the consideration of chucking, which we shall enlarge a little more upon.

The chuck is a very necessary and even indispensable auxiliary when chasing. Threads cannot be caught in the jaws of a scroll chuck, because, if set tight enough to hold the work, the threads are jammed so that they will not run in the part they were fitted to. If a piece, having a thread cut on it, like Fig. 29, is to be turned outside, it is very easy to chase the cap first and then the cup it fits, so that the cap can be screwed into it and turned off where it belongs; it will then be true, and is easy to mill on the edge.

It must always be borne in mind that the chaser must be sharp. If it is not, drunken threads will be the rule, not the exception.

The chuck shown in Fig. 30, will be found very useful for holding metallic disks, small box covers, or anything that requires merely a slight clasp; it is also useful for holding round plugs, pencils of wood, or penholders, to drill in the ends. It can be made eccentric with the mandrel of the lathe, if desired, so as to turn a piece on one side, or drill in a similar manner in the end of a plug. It is merely a piece of boxwood bored out, bored with holes, which are sawed down into slots, so as to form a series of jaws, which are sprung in by sliding the ring down on them. They are so easily made that a great many can be provided.

METAL SPINNING.

Spinning sheet metal into various forms is another kind of work which can be done in the foot lathe, and it is here that the amateur can show his taste and dexterity.

The process consists in forming a blank, like this engraving, into an ornamental base for a lamp, or an oil cup; in fact, any thing whatsoever. All that is requisite is to have a fac simile, in wood, of the shape you wish to make. This is bolted or otherwise made fast to the face plate, and the blank is then set up against it, and held as the cylinder head, shown in Fig. 26, is, that is, with a rod leading from the back center of the lathe to the work.

A tool like Fig. 32 is then used to press the metal into all the recesses or curves of the pattern. The speed must be high, and the metal quite soft and moistened with a little soap-suds or oil, so that it will not be scratched by the tool.

To spin metal requires some dexterity, but it is easily acquired after a little practice. The rest must be furnished with holes, like Fig. 33, and a pin, so that the tool can be brought up against it like a lever.

Still-another kind of metal spinning can be done in the lathe. This relates to making circular shapes, or cylindrical, more properly--such as napkin rings, the tops of steam pipes, or similar things. To do this, a mandrel is requisite. The mandrel must be of steel, and turned to the desired pattern--like Fig. 34, for instance.

We know of no prettier or more expeditious process of making a small steam boiler for a toy engine, than by spinning it upon the lathe. The boiler will be very strong, have large fire surface, and be without joints, having only one at the bottom, where it is easily kept tight. Fig. 36 is the boiler.

The metal must be thin , the sheet brass sold in the shops will answer, as it is already annealed, and the corrugations must not be too deep on the sides, or the work will not come off the mould. The center of the fire-box, A, must be left flat, so that the flue will have a bearing on it. For a small engine, 1-inch bore, and 2-inch stroke, a boiler of the dimensions given here is ample. The flue must be brazed or soldered at A, and the bottom must be riveted at B, for every two inches; this is not necessary, however. There are only three pieces in this boiler--the shell, the fire-box, and the flue, and the water must not be carried more than three-fourths of an inch over the crown of the furnace.

We shall now again revert to cutting tools.

Probably many of our readers, who use hand lathes not furnished with slide rests, have wished for that indispensable appendage where boring is to be done. For ordinary turning, we do not appreciate a slide rest on a hand lathe so much as many do that we know, but for boring out valves, cocks, or, in fact, anything, a scroll chuck and a good slide rest are invaluable.

Some persons are always "meaning" to do a thing, yet never do it. Sometimes, for the want of facilities, at others for the lack of an idea. If the latter be of any value, we can furnish one or two on this subject that may be useful.

One way to bore out holes parallel, without a slide rest, is to do it with the spindle of the back head. With a tool of peculiar construction, holes varying in size, can be bored beautifully in this way. We present a view of such a tool in Fig. 37. It is merely a cross, formed on the end of a center fitting the back spindle, the same as the lathe center does. The arms of the cross are made stout and thick, so as to admit of a square hole being cut in them. The hole is made by drilling in and driving in a square drift afterwards to take off the corners. The shanks of the tools are well fitted to these holes in the arms, so that a slight pressure of the screws in the sides of the arm will hold them steady. When used, the tool is put in the back spindle, and the cutters set to the size required, or less, if there is much to take out, and run through the work in an obvious manner. Any range of size can be had up to the diameter of the cross. It is not well to run the cutters out too far, however, as they will jump and chatter, or spring, and make bad work. The tool is so easily made that one can afford to have three or four, for different jobs.

Another plan, but not so good, is to make a common center and disk, like Fig. 38.

Here the cutters have a slot in them, through which a bolt passes and screws into the disk; a small piece of wood put at the bottom of the tool, between it and the cutter, prevents it from slacking off so as to diminish the cut. These tools will be found useful, and will do good work if properly handled. This latter tool is better for wood, but will answer for any metal by varying the cutter.

To make a slide rest, in the common way, is a costly and tedious job. For all purposes of boring, a good one may be made as shown in the following engraving, Fig. 39.

ORNAMENTAL CUTTING.

I shall now give some examples of turning different things which are useful and interesting to work. These are only hints, and I make no claim to discovery, or to anything specially novel or ingenious. It would be very foolish to do that, for what seems remarkably "cute" to the designer of any particular thing, is often shown to be slow and unmechanical, compared to other ways by other men. I hope, therefore, that the expert will bear in mind the fact that, while he may know better ways to do the same thing, beginners are glad to receive instruction first, and improve upon it, so much as they are able, after.

TO MAKE A PAIR OF SOLITAIRE SLEEVE BUTTONS.

Go to any dealer in box-wood, and procure waste stuff, which he will sell at a small price. Take a piece an inch square, put it in the chuck, and turn it round on one end as far as you can, then reverse it, and turn the other end; this will make a round plug. Take a ten-cent piece, and chuck it, either in a wooden or scroll chuck. Cut out the center, so that you have a silver ring. It will be necessary to have two rings, one for each button. Put the box-wood in the lathe and turn the end as in Fig. 41. On the shoulder you are to shrink the silver ring just made, Fig. 40. To fasten the ring properly, you have only to leave the center part of the box-wood a little larger than the silver ring--say the thickness of a sheet of paper--heat the ring slightly on a stove or over a spirit lamp, and clap it on to its place. When it is cool, if properly done, no power can remove it without destroying the button. When the ring is in place, it only remains to turn it off as ornamentally as the workman desires. The edge may be milled, and the face chased or left smooth. The center of the button, which is of wood, may be drilled in, and a square ebony plug put in, which will give it a unique appearance, as shown in Fig. 42. In like manner ivory buttons may be turned and breastpins spun up, either in gold or silver. Brass breastpins may be ornately turned, and afterwards electro-plated for a trifle. They will thus be cheaply made, and the ingenious turner can please his lady friends by presenting them with specimens of his dexterity and taste.

At the commencement of this book, I alluded to lathes with traversing mandrels, and to varieties of work done by tools not generally employed--that is, those which are not used by the hand, but in connection with the lathe, and driven by belting from a counter shaft over head. I give an illustration of such a tool, in one form, in Fig. 43. It may be screwed in the tool post of the slide rest, or otherwise attached to the lathe, and the belt from the counter shaft carried over the small pulley. The driving pulley over head should be very large, so as to give a great velocity to the cutter, at least fifteen hundred revolutions per minute. The use of this tool is to make ornamental designs--circular carving, it might be called--on all kinds of turned work, as, for instance, in Fig. 44, where a small box for pins or needles is shown. This box is made by putting a piece of hard, fine-grained wood in the chuck, boring the hole and cutting the thread. It is then removed, driven on a round mandrel held in the chuck, turned off round outside, and then prepared for the pattern as follows:--The design settled upon, the index plate must be brought into use, and the points inserted in such holes as will bring the pattern out right, or all the spaces equal--just as the teeth of gears are cut. The tool shown in Fig. 43, may be any desired shape. In the example of work, Fig. 44, it is made half round, and the pattern is called "bamboo," from a resemblance to wickerwork. The pattern is made to break joint, as mechanics say, that is, it alternates, so that the commencement of one part meets in the middle of the other. After one course is made all the way round, the tool is shifted on to another course, and the index changed as above mentioned, until the whole has been gone over. This produces a beautiful effect.

It is easy to see that a change of pattern is produced at will, by altering the kind of tool and the index. As, for instance, in Fig. 45, where the pattern is entirely straight. When the design is to be cut on such work, it is extremely convenient to have a pair of centers to set on the lathe, across the bed; then the flying tool is not needed, nor the index on the lathe pulleys either, that on the centers being used instead. When this box is held between the centers so as not to mar it, the handle may be turned and the work run along under the cutter, with great facility. The grooves shown in the box are first drilled at each end with a common drill, just to the corner of the drill, so that a neat and handsome finish is given; a V-shaped cutter is then put in a mandrel between the centers of the lathe, and the pulleys set going, so that when the work is run under the tool, the slot or groove will be formed. The circlet, at the top of the box, is made by a crescent drill ground very thin and made sharp--a drill like a fish's tail, only formed on a half circle.

Of course, these methods of doing this kind of work can, as I have said before, be varied infinitely, and are only cited as applicable to a common foot lathe.

CENTERS.

An indispensable article on a foot lathe, where any fancy work is to be done, is the centers--of which I have before spoken--shown in Fig. 46. These consist of a common set of heads, with spindles fitted to them. One spindle has an index plate and spring, and the other has a common center. These heads set on a slide that is moved back and forth over a rest, screwed to the lathe bed as usual. It is easy to see that, with this, we can do some very fine cabinet work. Suppose we have a round vase turned up handsomely, and wish to flute the base or make it a series of curves all round; to do this, we have only to put it in the centers, set the index so as to come out even, as before explained, and go ahead.

The centers can be set at any angle with the cutter shaft and a pineapple pattern can be made on straight surfaces, by executing one part at one angle, then reversing the rest that carries the centers, and finish the remainder, one part of the pattern crossing the other.

I present here views of a novel ornament which exhibits great mechanical ingenuity and manual dexterity, but is otherwise of no value. It consists, in one form, of a globe with a series of rings or globes inside, and a six-armed spur projecting through holes--all cut out of one solid piece. Fig. 47.

Fig. 48 shows how the points are turned. After the internal rings are cut out with a quadrant tool like Fig. 49, and the spur also severed, by cutting in the ends of the holes , the globe is put in a shell chuck, with three set screws in it, as shown. The set screws go through the holes in the globe, and the cross pieces, in between the spurs, serve to steady the job. Any number of points may be turned in the globe. Fig. 50 shows a polygon with many spurs turned inside. At first sight it would appear that the tool, severing the rings, would cut off the points also, but it will be seen that this is not the case, for the holes being bored so as to leave a core standing , the severing tool falls into the holes and goes no further, and each division serves as a guide for the tool in the next hole, so that the globe is made the same size, without jags. The quadrant tool, shown before, must be followed round the shell in the act of cutting it out, so that it will make the same round, and the globe must be shifted in the chuck, to reach all the holes. It is no easy task to make this little affair, for all it looks so simple.

FANCY TURNING.

Fig. 51 is another, a little more ornate and of a different pattern. The process is essentially the same, except that there are no spurs and a solid disk is left inside. This disk is turned out of a ball, left inside the exterior shell. One side of it is squared up before the ball is cut free from the globe, and the job is then reversed and the other side squared. The ball is then cut free, and the loose disk is held fast between a flat-ended driver in the live spindle, and a loose, flat-ended button on the back center. The diameter is then decided through the hole which is toward the reader.

A little tool, which is very convenient for making small screws, is here shown in Fig. 52, rather out of place, but it was overlooked before. In construction it explains itself. Holes of different sizes are made in a steel rod, and the end filed into shape, as seen. It has been found difficult by some to make these cutters work, but that was because they were not properly made. The trouble lies in drilling the hole. When the drill starts at first, the hole is larger on the outside, so that the screw blank, when cut, gets tighter as it goes in, and twists it off.

The remedy is, to drill the hole in some distance and then turn off the outside end, so that it gets where the bore is the same size. This refers only to small bolts, a sixteenth of an inch in diameter; where they are large, the trouble mentioned is not experienced.

It is convenient to have two sizes in the tool so that the heaviest part of the work can be done by one cutter, the tool reversed by turning it over in the fork of the jaws, and finishing the blank with the last cutter. A watchmaker's fine saw is to be used to sever the screw from the rod. The tool itself is to fit in the spindle of the tail stock, and the screw wire is held by a drill chuck.

In the matter of ornamental work, there are other details and plans in vogue among experienced turners, which can only be alluded to, not discussed at length, for the reason that the styles are so numerous that an elaborate work might be made of them alone, with great profit. The scroll chuck or geometrical chuck, as it is sometimes called, is a complicated piece of mechanism, too costly for general use, and too limited in its application, to mechanics in general, to be of much utility. It does such work as may be seen on bank bills. The chuck plate, on which the work is fixed, is connected, by a train of gearing on its back, with a fixed gear about the spindle on the head stock, so that when the relation these gears bear to one another is altered, the motion of the work on the chuck is accelerated or retarded, or is made to assume certain positions. An elliptic chuck is quite another thing, the work done by it is shown in Fig. 53, which consists, chiefly, of ornamental designs disposed in a certain order. In fact, the changes that can be made are infinite.

Mandrels--arbors, as many call them--are very useful tools. Mandrels are made of wood and steel--usually steel, and never of wood, unless for some special reason. As, for instance, when a large brass ring has to be turned. For this use a wooden mandrel is cheaper and more quickly made than a steel one. Besides, it is quite as good. Wooden mandrels should have iron center plates let in them, so that they will run true; if the center was made in the wood itself, it would be liable to run out. Take a piece of sheet iron, one eighth of an inch thick and one inch square, hammer the corners thin, then turn them over at right angles with the plate. This gives four sharp corners, so that, when driven in the end of a block, it will not slip; three small screws will hold the plate to the mandrel so that it cannot get loose. The center must then be countersunk, as any other is. Such a mandrel, made of hard wood, hickory for instance, will last a long time.

Fibrous wood such as white oak, makes a good mandrel, for the reason that work, driven on it, compresses the fibers instead of scraping them, so that the size of the mandrel is unchanged.

Steel mandrels should be turned two in one, or largest in the middle, for small work, each end being a different size. Each end should be thoroughly centered with a drill, and countersunk, and a flat place filed so that the dog will hold; not a scratch with a tool should ever be made in one, though few persons will take the pains to avoid doing this.

It is unnecessary to tell the mechanic he must have a rack for his tools, but we may tell the beginner so, and he will find it a great convenience.

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