Читать книгу The Boy Craftsman - A. Neely Hall - Страница 6

Before using a tool be sure you understand the proper handling of it, for there is probably nothing more easily injured than an edge tool in a sharpened condition. An inexperienced person is very apt to dull or nick a tool by striking its edge against nails or by using it for purposes other than what it was made for. For this reason a carpenter is very apt to refuse a boy, or any amateur for that matter, the use of his tools, and he is right in doing so. Just imagine the amount of work it makes for him to put the tools in shape after they have been returned in all sorts of conditions. A little rubbing on the oil-stone, with an occasional grinding, is all his tools require when he is using them, but to remove nicks made by his young friends wastes too much of his valuable time.

A good rule to observe, boys, is never to lend tools to any of your friends, for though they may be as careful in handling them as you are, the chances are they will not be. You had better be a little "grouchy" in this respect, than to have tools which are unfit to do good work with.

The following directions, together with the illustrations, should make the handling of your tools perfectly clear, and you will find among these a number of hints as to the care of tools that should be carefully adhered to in order that you may keep them in good condition.

Fig. 19.—Teeth of Cross-cut Saw.

Saws.—A boy can get along with two saws, a cross-cut saw for general use and a compass-saw for finer work, such as circular sawing, and cutting thin wood where a large saw would be too coarse and apt to split the work. But you will often have need of a rip-saw, back-saw, and bracket-saw. They were therefore included in the list of tools on page 14, and you can add them to your outfit as your money permits.

The Cross-cut Saw is, of course, intended for cutting across the grain, while the rip-saw is for cutting with the grain, or ripping. The former saw can be used for rip-sawing, but the operation is much slower, and when you have much of it to do, as in ripping a six-foot board, for instance, you will find the work tedious.

The Rip-saw is not fit for cross-cutting, as it leaves the cut fibres in a very rough condition.

The difference in these two saws lies in the shape of their teeth. This can be seen by picking them up and examining their cutting edges. You will find the teeth are bent out of line, the first to the right side and the next to the left. This is known as the "set" of the teeth, and the quality of your work will depend largely upon the care with which the teeth have been sharpened and set. At first you may confuse these two saws, but if you will notice that the teeth of the cross-cut saw come to sharp points and are bevelled on the sides, while those of the rip-saw are not sharpened on the sides, and instead of being pointed on the ends are chisel-shaped (see Figs. 19 and 20), you will have little trouble in distinguishing them.

Fig. 20.—Teeth of Rip Saw.

Sawing.—Small pieces may be sawn while held in the vise, but, as a rule, large work is placed across a couple of horses. It is generally the most convenient way. Grasp the saw in the right hand, and take the position shown in Fig. 21, with the left knee upon the work to hold it in place, and the left hand at the edge of the board. The thumb should be pressed against the saw-blade to guide it until the cut has been well started, as shown in Fig. 22. Without the aid of the thumb the saw is liable to slip off the mark and make an ugly cut in the wood. First use a few short strokes until the saw has started to cut. Then use a long, steady stroke, putting all of the pressure upon the down stroke. Be careful to keep the saw to the line and in a perpendicular position, so that the cut will be square on all sides. If it starts to run away from the line, a slight twist of the blade will return it.

Figs. 21–22.—Position for Sawing.

When a board has been sawn nearly in two, remove the weight of your knee from it, and hold the board with the left hand to prevent it from splitting off.

Fig. 23.—Position for using the Back-saw.

Fig. 23 shows the correct position for using

The Back-saw, which is intended for more delicate work than the larger saw, such as can be sawn on the bench-hook or in the mitre-box. It makes a finer cut, its teeth being smaller and more closely set.

The blades of

The Compass-and Gig-saws are small and narrow, the former being used for circular cutting, as the name would imply, while the latter is employed in cutting very thin wood and in making delicate curves. The blades of these saws, especially the latter, are easily broken, and must be handled with care. The teeth are arranged so as to cut with and against the grain.

The slot made by removing the fibre of the wood in sawing is known as

A Kerf. The term is used a good deal in carpenter work, so it is well to know its meaning.

The carpenter of to-day is generally supplied with all manner of planes—rabbeting-planes, beading-planes, circular-planes, ploughs, etc.—besides the more commonly used jack-plane, fore-plane, and smoothing-plane. Each of these planes has a special form of work to do, but ordinarily a boy will have occasion to use but the last three named, and many get along with but a jack- and a smoothing-plane.

The Jack-plane is the plane you will first need to remove the rough surface of undressed lumber, and also to reduce quickly the thickness of wood. The cutting edge of the blade is ground so as to gouge the wood, removing thick shavings, but leaving ridges and hollows which must afterward be removed by a fore-plane or smoothing-plane. There is one trouble in using the smoothing-plane for this operation, however, and that lies in the danger of it following the hollows formed by the jack-plane, making a smooth but uneven surface.

The Fore-plane, on the other hand, has a long enough stock to prevent the blade from cutting the lower portions until the high portions have been removed. Although a fore-plane can be used alone for smoothing large work, it is more convenient to finish up with

The Smoothing-plane.

The Stanley iron plane, shown in Fig. 24, is a great improvement over the old-style wooden ones, and is the most popular plane used to-day. It is more easily handled, as its iron is quickly put in place and adjusted. The illustration gives the names of the various parts. The cap (B) is screwed to the plane-iron (A), and both are held in the stock (F) by means of the clamp on the end of the wedge (C). The thumb-screw (D) regulates the degrees of fineness of the plane-iron, while the lever (E), which moves from side to side, straightens the position of the iron. The base of the stock is known as the sole, or face.

Fig. 24.—Stanley Iron Plane.

A. Plane-iron. B. Plane-iron Cap. C. Wedge or Clamp. D. Adjusting Screw. E. Adjusting Lever. F. Stock.

The Bailey plane is somewhat similar to the Stanley, the upper portion being of iron with screw adjustment, but the base being of wood. Its cost is much less than that of the entire iron plane, and you will probably find it as satisfactory if you do not care to spend the additional amount for the Stanley plane.

For Planing, take the position shown in Fig. 25, with the left foot a little in advance of the right, the right hand grasping the handle of the plane and the left holding the knob on the fore part of the stock. Use a long, steady sweep, and bear with equal pressure from the beginning of a stroke to the end, to avoid the hollows that are so easily made by taking shavings of different thicknesses. Do not drag the plane-iron over the work in returning it for another stroke, as it will dull its edge.

You will often come across wood with a crooked grain, which runs diagonally through the piece, terminating at the surface. There is a right way and a wrong way in planing this, just as there are two ways of stroking a cat's back, one smoothing the surface, while the other roughens it. When you find a piece of wood with this kind of uncertain grain, you will probably have to change the direction of your planing a number of times before finishing the surface, in order to plane with the grain.

Fig. 25.—Take this Position for Planing.

In planing end-wood, you will have trouble in preventing the corners of the piece from splitting off unless it is placed in the vise in front of another block of wood, the planing being done toward the block. Or one corner may be chamfered with the chisel, as shown in Fig. 29.

Testing Work.—It is necessary to test work frequently while planing, in order to locate the high places and avoid taking off too much on the low places. This may be done by squinting one eye and holding the board on a level with the other eye, so that you can look down the length of it as in sighting a gun. The uneven places show up very plainly in this way.

Work is also tested by means of the try-square. Place the handle of the square against the edge of the work with the blade of the square extending across the planed surface, and move it the length of the board. Any irregularities in the surface will show themselves as the blade passes over them. In planing up a block of wood, plane up one side and, after proving it to be true, use it for the "tried edge," testing the other sides with the handle of the square pressed against its surface.

There are a number of forms of

Chisels, but the only two classes you will probably ever be in need of are the firmer-and framing-chisels. The former are intended for hand use only, while the latter are used for heavier work, such as mortising, where it becomes necessary to use the mallet.

Figs. 26 and 27.—Paring.

In Using a Firmer-chisel, the work should be placed in the vise or be otherwise held in position, that both hands may be kept upon the tool, the right hand grasping the upper end of the handle and doing the pushing, while the left hand holds the lower part of the handle and acts as a guide in working it.

Paring with the chisel consists in trimming a piece of wood to a given line. It is an operation very often resorted to in finishing the end of a piece of work instead of planing, and in trimming up a curved edge such as is shown in Fig. 26. Here the line AB represents the line of the finished end of a piece of work. The board is first placed in a vise and the wood removed to about one-quarter inch of AB with a compass-saw, following the curve of the line as nearly as possible. Then lay the piece upon the bench-hook (Fig. 11, Chap. I), and pare to the line with the chisel, as shown in Fig. 26.

The chisel is often used to pare down the surface of a piece of work to a given line, as shown in Fig. 27.

Fig. 28.—Bevel.

The Framing-chisel should be held in the left hand, and the blows dealt upon the handle with the mallet in the right hand. In handling the framing-chisel the bevel of the blade should be toward the work, which is just the opposite from that shown in Figs. 26 and 27. Unless this is done the chisel will not cut down squarely but will cut in under, as it cannot be guided as easily as the firmer-chisel can, with both hands to hold it.

Chamfering and Bevelling are somewhat similar operations. They consist in cutting the edges of a piece of wood, as shown in Figs. 28 and 29.

Fig. 29.—Chamfering.

The corner of a block of wood is very often chamfered, when planing end-wood, to prevent the wood from splintering. It can only be done, of course, before the adjoining side has been planed up, that a square corner can be obtained again when the work is finished.

The Gouge is a chisel with a curved section, its use being for cutting grooves and curvatures in a piece of work where the chisel cannot be employed.

A Draw-knife is very handy for quickly reducing the size of material and in rounding sticks. The blade is drawn toward you instead of being pushed as in the case of a plane or chisel.

Boring.—Probably the only trouble you will have with the bit and bit-stock will be in holding the brace in a perfectly vertical position so as to bore a straight hole.

The centre of the hole should first be located upon the work. Then, after selecting the right size of bit and securing it in the clutches of the bit-stock, grasp the handle of the stock with the right hand and place the left hand on the top knob. Set the point of the bit against the work and bore steadily until the point appears upon the opposite side. The bit should then be withdrawn and the rest of the hole bored from the other side. This prevents the fibre around the hole from splintering off, as it is likely to do when a hole is bored all the way through from one side. To bore a hole in a piece of work held in the vise, clamp a waste piece of wood in the vise with it, and bore straight through the work into the waste piece.

When boring hard wood or using large bits increased pressure is necessary to operate the brace and at the same time steady the bit. This can be obtained by allowing the chest to bear upon the top knob.

Holes two inches or more in diameter do not require a bit that size, for smaller holes can be bored and these trimmed to the required opening with a chisel or with the keyhole-saw. Whatever style of bit-stock you buy, get one with a fair length of arm, as a good leverage cannot be obtained with a short one.

An Automatic-drill is a handy tool to have in the shop, although not a necessity. You have probably seen carpenters use it in drilling holes in hard wood, before driving in finishing nails or screws. It beats the awl and gimlet for speed, and is a tool which can be used in places where neither of these could be operated. The handle of the tool contains a number of sizes of drills.

This tool must be used with care, as the drills snap off very easily when the tool is handled roughly or twisted from side to side while boring a hole.

The Hatchet is an indispensable tool, for it can be used for a good deal of your rough work, such as splitting and paring. It requires practice to handle one successfully, however. A misplaced blow will sometimes ruin your work, either by cutting into it or striking grain which runs off into the portion to be finished. With straight grained wood it is not so difficult to pare to a line with the hatchet. The wood should be removed to within less than an eighth of an inch of the line, as the work must be dressed up afterward with the plane.

It is well to have

A Hammer with a fairly heavy head for large work, and a lighter one with which to drive small nails.

Fig. 30.—Withdrawing Nails.

Driving Nails.—The nail should first be held in position with the thumb and first two fingers, and given a few light raps with the hammer to start it. Then remove the fingers, and drive the nail home with steady blows, being careful to hit the head squarely so it will not bend.

Although a bent nail can be driven home with the proper stroke, it is generally easier and quicker to withdraw it and either hammer it out straight or use another.

A pair of pincers are handy for

Withdrawing Nails, especially nails whose heads are too small to be gripped with a claw hammer; but for removing large nails a stronger leverage is necessary. This can be obtained as shown in Fig. 30. The head of the nail is gripped in the claw of the hammer and a block of wood placed beneath the head. The handle of the hammer is then pulled toward you, as shown in the illustration. The block, besides increasing the leverage, prevents the hammer-head from injuring the surface of your work, and makes it possible to withdraw the nail in a fairly straight condition.

Fig. 31.—Toe-nailing.

Toe-nailing consists in driving nails diagonally into a piece of wood. It is used in fastening the ends of uprights, as shown in Fig. 31, where the nails cannot be driven in any other way, and also where there is danger of a board springing. You will often find it convenient to use this form of nailing when the nails are too long to be driven straight into the work.

Blind-nailing is a form of toe-nailing used on tongue and grooved boards in which the heads of the nails are concealed below the surface, as shown in Fig. 32.

Clinching.—When nails come through a piece of wood their ends should be clinched. This is done by having some one hold a hard surface, such as the head or blade of a hatchet, against the under side of the work, or by laying the hatchet down and resting the work upon it, while you drive the nail. The point of the nail will bend over when it strikes the hard surface and sink into the wood. This is the best method to use in fastening boards together with battens, in rough work, as the clinched nails act as rivets, preventing any possibility of the boards pulling apart.

Fig. 32.—Blind-nailing.

Do not drive the head of a nail into a finished surface with the hammer, as you are likely to mar the wood in doing so. Leave this—the "setting" of the nails—until the piece of work has been put together. Then go over it and drive the heads below the surface with

The Nail-set, holding the tool as shown in Fig. 33. The holes made by the heads should be filled up with putty before the finish is put upon the wood.

Before driving nails into hard wood, holes should be made with the brad-awl or drill, to prevent them from splitting the wood, and to make it easier to drive them in without bending. The holes should be a trifle smaller than the nails. Always drill a hole before driving a nail into thin wood or near the edge of a piece.

A nail can be driven more easily if its point is rubbed over a piece of soap. This is something you should remember to do when nailing hard wood.

Nails.—Iron, galvanized-iron, wire, and copper nails are manufactured, but of these the wire nail is the most commonly used for all kinds of work, it being more easily handled, not so liable to snap off, and there being less danger of splitting your work with it than with the iron nails.

Fig. 33.—Setting Nails.

You will notice the iron nails have two smooth sides and two rough ones. In using these it is necessary to drive them with the smooth sides parallel with the grain, otherwise they are sure to split the work.

Nails are classified according to their shape and gauge. The only kinds you will probably ever have occasion to use are the Common, or nail for all ordinary work; the Finishing-nail, with the small head used on finish work; and the Brad, or small-sized finishing-nail. You can buy these by calling for the length you require, but it is more businesslike to use the standard terms by which all carpenters know them.

The following table gives these terms, together with the length in inches:—

2-Penny Nails (1 inch long).

3 " " (1¼ inches long).

4 " " (1½ " " ).

5 " " (1¾ " " ).

6 " " (2 " " ).

7 " " (2¼ " " ).

8 " " (2½ " " ).

9 " " (2¾ " " ).

10 " " (3 " " ).

12 " " (3¼ " " ).

16 " " (3½ " " ).

20 " " (4 " " ).

30 " " (4½ " " ).

40 " " (5 " " ).

50 " " (5½ " " ).

60 " " (6 " " ).

All nails longer than three and a half inches (20d to 60d inclusive) are known as spikes.

It is desirable to have

A Screw-driver which will set in the clutches of your bit-stock, besides the ordinary kind, for it is more quickly operated, and screws can be driven in hard wood easier on account of the greater amount of leverage you get with it.

Holes should be drilled in hard wood before driving screws into it.

Screws are made with round and flat heads. The round-headed screw is a finishing screw, and its head is left exposed on the surface of the wood; but the flat-headed screw should be countersunk, that is, sunk below the surface. To do this you must drill a hole before driving in the screw with

The Countersink, which is a drill made to fit in the bit-stock, and bores a hole the shape and depth of the screw-head.