Chapter II: Preface (2)

For the driving gear, three disks shown at _a_ (Fig. 47) were sawed out, the two large ones, 1-1/4 inches in diameter, from 1/8-inch basswood. The edges of these two were rounded with knife and sand-paper. The small disk, 3/4 inch in diameter, was cut from 1/4-inch wood or two 1/8-inch pieces placed together and glued.

A square hole was cut through the centre of each of these disks with a knife, and they were then put together with glue and brads, making a very serviceable grooved pulley, which was slipped over the shaft and fitted over the square part in the centre. As it was a snug fit no glue was necessary, and the square part prevented the pulley from slipping on the shaft. The forward axle was made 3-3/4 inches long, 1/4 of an inch square, except at the ends, where for a distance of 5/16 inch it was rounded, 1/4 inch in diameter. This completed the wheels, axles, and transmission pulley.

The chassis, or frame, which supports the body, consists of two pieces of 3/16-inch basswood 8 inches long and 1/2 inch wide, with a 1/4-inch hole drilled 1/4 inch from each end. The floor of the auto, on which the body rests, is 1/8-inch basswood 6 × 3-1/2 inches, and it binds the whole machine together, giving it strength and rigidity, but it must not be fastened in place until the structure is ready for assembling.

The hood is simply a box 3-1/4 inches long, 2-1/2 inches wide, and 1-1/4 inches high without a bottom. The top piece may be left unfastened, if desired, with two cleats on the under side to hold it in position. The hood then becomes an available place to keep small articles, tools, etc.

The body of the automobile is composed of five pieces: the two sides of the shape shown at _b_, the dash-board, to which they are fastened with brads, the seat, and the back. This body can be taken off and replaced by other bodies, made to represent roadsters, touring cars, limousines, etc.

A block of 1/4-inch basswood 3/4 inch square is fastened to the dash-board. This block has a 3/16-inch hole drilled through it at an angle of forty-five degrees, and into this hole is glued the steering-gear, consisting of a basswood stick, whittled to 3/16 inch diameter, with a 1/8-inch wheel 1-1/4 inches in diameter fastened at the top, _d_.

The method of assembling is important. First, insert the front and rear axles through the holes or bearings in the chassis, or frame; then nail the floor to the frame with 3/8-inch brads. This gives a rigid structure to work on, the front edge of the floor being even with the forward ends of the frame. Now screw into the under side of the floor, 1-1/4 inches from the front end, a 1/2-inch screw eye or screw hook, or even a flat-head nail. This is to hold one end of the rubber band which is to supply the motive power.

The hood may now be put together and fastened even with the front of the machine by nailing it from the bottom with brads. The body is put on by nailing the two sides to the dash-board, and the dash-board to the hood. The seat and seat-back are afterward put in place with brads and the steering-gear glued in position against the dash-board.

The wheels should be put on last of all. Before placing them in position, slip two or three new rubber bands over the screw hook under the car, and tie the free end to the driving pulley so tightly that the cord will not slip on the pulley.

The front wheels are fastened to the axles by 1/2-inch flat-head wire nails, and worked until they revolve freely on these pivots; the flat head holds the wheel on.

The rear wheels are the drivers, and must be fastened rigidly to the axle by glue. When the glue has hardened--this takes several hours--the machine may be sent across the room on the floor by winding the rear axle backward as much as the rubber bands will permit without breaking, and setting the machine on the floor.

The first time the boys tried it, the rubber band uncoiled so quickly that the auto shot across the room and nearly wrecked itself against the wall. This was too realistic, especially as it broke one of the forward wheels, and a new one had to be made.

When such an automobile is to be presented to little children who want to draw it around with a string, it is necessary to remove the rubber band; otherwise the rear wheels will drag.

When our boys had finished their machine, the question came up to whom it should be given for Christmas, and Harry blurted out, "I want it myself." This was the greatest of all their difficulties. When they had finished a piece of work they hated to part with it, but Ralph was older, and he knew that as Harry became interested in new things he would gradually lose interest in the old ones. So they played with this machine, made another with a roadster body, and auto races became the rage for awhile. After several afternoons of racing, they decided, just as their elders had done before them, that what their machines needed was improved motive power. The accomplishment of this would take them out of the realm of woodwork, so Ralph suggested that they stick to their motto of "one thing at a time." "And our business just now is woodwork."

VIII

THE MODEL AEROPLANE

The automobile experiment naturally suggested the aeroplane, and after much reading of magazines and animated discussions as to the relative advantages of biplanes, monoplanes, gliders, etc., the boys decided to try their skill on a biplane of their own design, a combination of the features and proportions of the Curtiss and Wright machines.

The automobile was child's play compared with the problems confronting the young aviators in designing and working out a flying machine, and, as in the former case, the question of motive power was the most difficult. We might add it has not yet been satisfactorily solved.

Fig. 48 shows the general appearance of the boys' model, which was eighteen inches long from front to back, and the planes, made of light card-board, were 14 inches long and 3-1/2 inches wide. The frame, braces, rudder, and tilting plane were made of 1/8-inch basswood, put together with 1/2-inch brads clinched wherever the points came through.

The parts composing the frame were made first, and all small details, such as rudder, propeller, tilting plane, etc., cut out later.

The separate parts are shown in the drawing. Four straight pieces like _a_ were required to support the tilting plane in front, and two pieces each _b_ and _c_ for the rudder in the rear. Two pieces _a_, one of _b_ and _c_ were fastened together by means of two uprights _d_, forming one complete side of the machine. This was completed, and the second side made identical with it.

These two sides were then fastened parallel with each other, rigidly, by means of the two rudder posts _e e_ and the cross pieces _f f_, by brads. The rudder posts bound the two sides rigidly at the rear, the cross pieces at the centre, and at the forward end the tilting plane was held in position by the brads, which also acted as pivots.

This made a remarkably light and yet strong framework. The card-board planes were not placed in position until everything else was finished, as they could be attached easily and quickly, but were very much in the way when experiments were being made on the propelling apparatus.

Of course there had to be a propeller, and the problem of making it required some practice.

Ralph introduced the subject by showing Harry how to make an old-fashioned toy, shown in the detail drawing, of two pieces, one the propeller, the other a balancing stick.

The propeller was made of a piece of 3/8-inch basswood, 4 inches long and 1/2 inch wide. A 3/16-inch hole was first drilled at the exact centre. The two ends were then whittled down to the shape shown at _k_. The balancing stick was next whittled down until one end fitted tightly into the hole drilled in the propeller, and the rest of the stick then rounded until it was of uniform diameter. This stick was glued into the hole, and allowed to dry.

There was plenty of work to do while the glue was hardening, as the cross pieces _g g_ had to be fastened to the frame to prepare for the installation of the power plant.

When the glue was dry, Ralph took the balancing stick between the palms of his hands, drew his right hand toward him with a quick motion, at the same time releasing the stick. To Harry's amazement, the whole thing flew up and struck the ceiling, and for a few minutes aeroplanes were forgotten while the two played with this interesting but ancient toy.

Ralph explained that the propeller was simply part of a screw thread, and had actually worked its way through the air just as a screw works its way into a piece of wood. Its lifting power had been shown by the way it carried the balancing stick with it up to the ceiling.

"Now," he continued, "when we place a propeller horizontal it will worm its way forward through the air in the same way and carry the aeroplane with it, for the simple reason that it is so placed in the frame it can't get out. As the free space it has to revolve in is only 3 inches, we shall have to cut the blades down to about 2-3/4 inches to give it clearance."

They whittled out a shaft 1-1/2 inches long and fastened the two notched pieces _h h_ to it after placing the propeller in position between the two cross pieces _g g_ which had been previously drilled with 1/4-inch holes to act as bearings.

New rubber bands were then passed over the notches, stretched out to the front and rear of the frame, and tied to cross pieces.

By winding up the propeller, these bands were twisted tightly, and when the propeller was released, the bands unwound, causing it to revolve rapidly.

The rudder was now pivoted in position by brads, and the two planes fastened by the same method.

The power derived from the bands was not sufficient to propel the aeroplane fast enough to support it in the air, so it was necessary to experiment with strong thread until the centre of gravity was found. It proved to be near the centre of the planes. Small holes were made with an awl at this point, the thread passed through them and tied. By suspending the aeroplane from a chandelier it took up a horizontal position.

Then the forward tilting plane was elevated slightly and the propeller wound up. On being released the aeroplane slowly and majestically sailed through the air in a great circle, limited by the length of the suspending thread.

The boys never tired of this toy and all it lacked was the ability to fly in the open air, which would require a more powerful motor. This would more than double the weight of the machine, and therefore call for larger planes to support it. There you have the great problem of the aviator.

Ralph wisely suggested that as they had not yet reached the stage of designing gasolene motors they had better leave the aeroplane as it was, or it would be necessary to abandon their woodwork, which neither of them had any intention of doing.

IX

THE MONOPLANE

A very satisfactory monoplane can be made from the plans shown in Fig. 49.

The material for the frame should be quarter-inch white pine or spruce. The six long strips are 30 inches in length, and for fastening, holes should be drilled and the connection made by passing fine soft wire through them and binding fast.

The top frame, formed of four of these long strips, should be made first, with particular attention to the measurements, so that both sides shall be exactly the same size and weight.

At the rear end the two long strips may be wired together temporarily. The propeller shown in the drawing can be made at any time from a piece of white pine 7/8 inch thick and 12 inches long by 1-3/4 inches wide. It is a good piece of whittling work.

The 3/8-inch hole for the shaft should be bored first, and the propeller blades reduced to a thickness of 1/8 inch at the centre of the blade, and 1/16 inch or less at the edges.

The shaft needs to be strong, and should be made of a piece of 3/8-inch dowel rod. Make a saw cut with back saw in the end, which is to be fastened in the propeller.

When ready to assemble, push this end into the 3/8-inch hole in the propeller, drive in a soft pine wedge with a little glue, and a rigid fastening will result.

The groove in the rear end of the shaft is to take the thrust of the propeller, and hold it in the machine. This groove may be readily cut out with the knife, and smoothed with sand-paper. Two bearings are necessary to hold the shaft in alignment. The forward one is a strip of pine 1/4 by 3/4, with a 3/8-inch hole bored at the centre. This hole should be sand-papered until the shaft turns in it freely. The rear bearing is a strip 5/8 by 3/8 inch, laid out as shown at _a_. The quarter-inch hole must be bored first. Next, drill two small holes with a fine drill on either side of the hole for the wires which are to hold the two pieces together. Next saw on the pencil line shown, removing the small piece _x_. Test the bearing by placing the small grooved section of the shaft in the quarter-inch hole to see if it turns freely. When this has been accomplished, the propeller and its bearings are ready for the monoplane.

Looking at the front view, the two uprights are 9 × 3/4 × 1/4 inches. At the top ends they are rabbeted as shown, and wired to the top frame. At the bottom they are wired to the long strips which form the long sides of the bottom frame.

Before putting these uprights on, a 1/4-inch hole should be drilled 1-1/2 inches from the bottom of each. These are to receive the 1/4-inch dowel rod which acts as the axle for the spool _s_. This rod should be 10 inches or more in length, so that brads or wire may be passed through the ends outside the uprights to keep the axle in place.

The small spool which acts as a pulley must be perfectly free to turn on this rod, and be kept in place by two brads driven through drilled holes on either side of it.

The front and lower parts of the frame are now ready to be assembled.

The four long strips constituting the body of the frame are all wired together at the back, temporarily. To finish the forward part, saw out a strip 3/8 × 1/4 inch, and form on each end a rounded bearing, as in the automobile, for two wheels 1-3/4 inches in diameter. Saw the wheels out of 3/16-inch basswood, drill a hole at each centre, place on the bearing, and fasten in place with a flat-head wire nail and a small washer next to the wheel. Sand-paper the wheels smooth, and see that they turn freely. Tack the strip, or wire it to the uprights, as low down as possible.

The rear end of the monoplane is a nice little problem. Cut out a block of pine from 1 inch to 1-1/8 inches square. In the side facing the front place a screw eye for fastening the spring or rubber bands.

The rudder is shown in the drawing. Drill two holes, as shown, and drive in brads or flat-head wire nails, as large as the hole, so that the rudder may be turned by hand, but not free enough to turn with the wind.

Next drill a hole clear through the block for the axle of the tilting planes.

It is not necessary that the axle be at the exact centre of the cube. It should extend quite through both planes as well as the cube, and be bent around the edges, so as to make them rigid. They should be snug enough to turn by hand, but not loose enough for the wind to shift.

The four sides of the frame are now whittled down to fit the block, and wired to it.

Last comes the question of motive power.

This is _the_ great problem. The writer is opposed to encouraging boys to believe that these toy aeroplanes can be made to fly great distances. The propeller would have to be made to revolve at high speed for several minutes in order to accomplish this, and the tension of rubber bands is not equal to it. The machines can be made to fly short distances only. The problem of aviation is now a question of motors, and the smallest gasolene motor, with its tank, etc., requires a fairly large aeroplane to lift it. No doubt, the problem will be solved within a short time, but it has not been done at the time of writing.

For this size of toy monoplane several large rubber bands may be tied together, fastened at the screw eye on one end and to a piece of strong linen kite cord at the other.

Pass this cord forward under the spool and up to the propeller shaft.

Drill a small hole in the shaft, draw the cord taut, and fasten it through this hole.

While the model has no planes as yet, it is wise to get the propeller working before putting them on, as the space for working is freer. Wind up the propeller until the bands have been stretched to their limit, then let go. It may be necessary to place wheels at the rear, the same as in front. On a smooth floor, the machine should be drawn forward several feet by the action of the propeller.

It is entirely practicable, on a plane of this size, to use the works of an ordinary alarm clock in place of rubber bands.

Remove the outer casing of an old clock; loosen the four brass nuts that hold the frame together, and take out all the wheels, except the axle on which the mainspring is fastened. Put the frame together again with the four nuts.

The axle for the mainspring extends outside of the frame, and is threaded to receive the handle for winding. Take this handle off. Drill a hole in the end of the propeller shaft, slightly smaller than the mainspring axle, and screw the latter into the propeller shaft.

You now have the clock-works on the end of your shaft, and it is necessary to fasten a strip of pine 1/2 in. by 1/4 in. to the upper sticks of the frame in order to wire the works fast, as they must not be allowed to turn. By turning the propeller you wind up the clock, and as soon as you release it, as there is no escapement now to regulate the spring, it tries to unwind at once, and the propeller starts at terrific speed. Look out for your hands, as the propeller blades have no conscience.

This action, although strenuous, is short lived, but much more powerful than rubber bands. The spring of an ordinary alarm clock is powerful enough to drive a wooden two-bladed propeller 12 inches in diameter with blades two inches wide at the outside. It will draw a monoplane of this size along the floor several feet.

Having finally decided the question of power, it remains to attach the planes.

The remaining long strip is wired to the top pieces, 12 inches from the front, and the plane, made of silk, oiled paper, or very thin card-board, attached.

In many toy aeroplanes the bands of rubber are not stretched, but twisted. The shaft in this case is a wire which, after being fastened to the propeller, passes through a glass bead and then the frame, ending in a hook to which the rubber bands are attached. There must be a perfectly clear space from front to back of the frame. The glass bead between the propeller and frame is to relieve the friction.

X

KITES

Making and experimenting with aeroplanes calls for much patience and often ends in disappointment--the lot of inventors generally. This is no reason why work should stop, as all progress is made by attempting the supposedly impossible, but it will be restful after a while to turn to the ancient and gentle art of kite making.

Incidentally, something may be learned about the effect of wind on plane surfaces that will prove helpful in aeroplane work.

The aeroplane kite shown in Fig. 50 is simple and effective. It may be given the appearance of a Blériot monoplane by modifying some of its features, as shown at _b_, the planes having a slight upward slant. The arrangement of the frames is clearly shown in the drawing. Spruce or white pine may be used, as lightness is an essential.

The method of fastening the sticks is important. It is not wise to halve them, as their strength will be reduced below the safety point, and nails are likely to split them. Bind them securely with strong linen kite cord or fine soft wire.

Kite _a_ is open to criticism on account of the single stick connecting front and back. The second form is better, and the two long sticks may be correspondingly lighter without reducing the ultimate strength of the frame. The method of joining three sticks, as at the forward end, is shown in detail in Fig. 50. Wherever a butt joint occurs, join the two pieces by means of small strips of tin cut to size with a pair of tinsmith snips. Drill holes through tin and sticks, pass fine soft wire through the hole, and twist tightly with a pair of pliers.

The planes or sails may be of light, strong paper, or some light fabric, such as lawn or cheap silk. The fabric should be cut to size, allowing two inches each way for the hem. Pieces of cord are fastened to the hem, and tied to the ends of the sticks through small holes drilled for the purpose, or tied to notches cut with the knife.

The advantage of this method is that the sails, or planes, may be drawn tightly or removed without loss of time. In this way a number of fabrics can be used for experimental purposes. Paper, on the other hand, must be lapped over sticks and wires, and glued.

Propellers may be fastened to front, rear, or both, to create the appearance of a real aeroplane.

The restraining action of the cord holding one of these kites up against the wind brings into action the same force that supports the glider or aeroplane, and the sails, especially fabrics, assume the curve of a boat sail, when close-hauled and sailing into the wind.

The forms that are possible are infinite, and limited only by the imagination of the designer.

It is well to begin with one of the standard types, and leave experimental forms until some experience has been gained.

The Americanized Malay, Eddy, or parakite is shown in Fig. 50. The two sticks are of equal length, bound together with twine or soft wire. Distance _c e_ should be from 14 to 18 per cent. of the total length _c d_. The vertical stick remains straight, but cross stick _a b_ is bent back like a bow, the distance _e f_ being 10 per cent. of the total length of either stick, and maintained by a string from _a_ to _b_. The four points _a c b d_ are joined by a cord drawn taut, to make sure that the sticks are at right angles.

The material should be cut as shown, the amount lapped being uniform all around. This is important, as a slight difference in weight between the two sides would result in erratic flying. For Eddy kites up to three feet in height a light-weight wrapping paper will answer very well. Larger sizes require nainsook, lawn, or China silk. Like all the kites described here, this is a tailless one, and the method of fastening the bridle is shown. Make a small hole in the covering, pass a cord through, and tie it to cross the stick at its centre. Fasten the other end about half an inch from lower end of upright, and make a loop at _o_ for attaching the line.

The kite line should be the light and strong linen twine made especially for this purpose, and sold by toy and sporting goods dealers. A ball containing 600 yards of cord, strong enough to hold any three-foot kite, will cost about fifty cents.

For larger sizes, it pays to make a reel, to save time drawing in and to avoid bad tangles. A simple form of reel is shown in Fig. 51.

The frame has a generous-sized hole bored as shown at _h_. Cut a small branch in the form shown, _i_, and use this as a stake. Drive it into the ground through _h_, and use it as a pivot to shift the reel as the wind changes. With this arrangement the kite cannot drag the reel, and it is possible to leave the apparatus with the kite in the air. The writer was driven to using this device after seeing his reel go tearing across the fields until stopped by a four-foot fence. The pull exerted at the reel by a train of three or four kites is sometimes sufficient to give a boy all he can do to hold it. The height to which a kite will go is illustrated by the diagram. _S_ is the starting point, and _s t_ the direction of the string at the start, when but little cord has been played out. The position of the kite at various times is indicated by letters _a b c d e_, the actual path being shown by dotted line. The solid, curved lines from _s_ to these points show the position of the cord as it is played out. This is a mathematical curve resulting from the weight of cord and kite, wind pressure on cord, and lifting power of the plane.

It will be seen that the kite finally moves along horizontally, no matter how much cord is played out. This occurs when the lifting power equals the force of gravity and wind pressure. In other words, the kite can do no more without an increase of wind.

To make it go higher, we must raise point _s_ by tandem flying, attaching another kite and cord to the first one, as shown at _x_.

Three or four Eddy kites may be flown in this way, the lines of equal or unequal length joined at a common point to the main line; and, strange as it may seem, if they are well balanced kites they will not interfere with each other. In fact, there seems to be an electrical repulsion among the lines, so that they spread out like a broom.

This is one of the most interesting discoveries in kite flying, though badly upset in actual practice, when one member of the team becomes erratic and proceeds to make a braid of the four cords by diving under and over the others to bring about a general demoralization. For this reason, it is wise to test each kite separately, first, to discover any possible tendency to freakishness.

A weird experience may be enjoyed by leaving the tandem out after dark. Run the main line down by slipping it under your arm, and walk out until you reach the junction of the four lines, where a light-weight lantern can be attached. Let go, and see the lantern apparently drawn up into the air by noiseless, invisible hands.

Flags and other devices may be attached as indicated in the drawing; a light stick at _a b_ will keep the flag from blowing up into a heap, and loops at _a_ and _c_ are tied in the main line to avoid sliding.

THE BOX KITE

The cellular kite is made in several forms. The rectangular box variety is perhaps the most common, and with the bridle attached is shown in Fig. 51. The standard dimensions are: length _a b_ 79 inches, width _a c_ 78 inches, depth of cell _c d_ 32 inches, and width of cloth covering _c e_ 25 inches. A very convenient size is obtained by dividing approximately by two, making length and width 40 inches each, and depth 16 inches.

Mr. H. H. Clayton, of the Blue Hill Observatory, has patented one form of this kite known as the "Blue Hill Naval Box Kite," so the amateur must confine his use of it to experimenting. Other forms of cells which have been used are shown at 2 3 4 5. These all possess the advantage--that each plane is a lifting surface, whereas in the rectangular form the vertical planes have only a rudder action, tending to hold the kite parallel with the wind.

When launching a box kite, the assistant stands in front of and under it, while with the Malay he stands behind it and lets go at a given word. About a hundred yards of line should be run out before launching, and only a few steps backward by the boy at the string should be necessary. Running is only required when the line out is insufficient.

The tetrahedral form invented by Dr. Graham Bell is unique and interesting. Based on the geometrical figure, it has a remarkable strength of frame, and possesses a surprising lifting power. The principal difficulty in the construction is in fastening the sticks, as three of them meet at every point. The frame consists of six pieces of equal length. Drill a 1/32-inch hole in each end of all the pieces, about 1/4 inch from the end. Place the pieces on the floor as shown at 1. Pass a piece of soft iron or brass wire through the three holes at _a_ and bind lightly. Do the same at angles _b_ and _c_. Now raise loose ends _d e f_ until they meet over the centre, as at 2. Join with wire and tighten all the joints with a pair of pliers. (Fig. 52.)

Each face of the frame is an equilateral triangle, and the covering is to be on only two sides, as shown at 3. The shape of the piece to be cut is shown at 4. This forms a single cell, and the large sizes are broken up into many small tetrahedral cells. The line may be tied at _c_ or _d_.

The designing of fancy figure kites is a fascinating occupation, but unless certain fixed principles are kept in mind may end in much experimenting and many disappointments. The question of steadiness or stability seems to be summed up in the mathematical expression--"dihedral angle."

A kite having a stiff, flat surface presented to the wind will often cut up queer antics, while the same frame covered with a more flexible covering will fly beautifully. The reason is that the flexible covering will be bowed back by the wind, forming an approximate "dihedral angle."

In the triangular box and tetrahedral kites this bowing back is not so necessary, because the dihedral angle is provided in the construction.

In these kites, when a sudden gust of wind presses harder on one side than on the other, the first side is pressed back, reducing the resistance, and the other side is brought forward until both sides receive equal pressure, or the kite is in equilibrium, facing the wind; and the shifting of the breeze is constantly provided for. The bowing back of the covering of an Eddy kite takes care of sudden changes in the same way. Double Malay kites or two tetrahedral kites, fastened together, tandem fashion, will be found stable, especially if the rear one be slightly smaller than the forward one. (Fig. 53.)

Geometrical forms like the hexagon, six-pointed star, and even the circle are used, but these generally require a tail.

A butterfly design may be used, provided the body is designed as a keel and the two wings are tilted backward to provide the required angle. In some of the Chinese kites, in the form of insects, the wings have split bamboo frames, flexible enough to bend backward and provide the necessary stability. A flexible lower end on the frame also has a good balancing effect.

XI

CHIP CARVING AND KNIFE WORK

"Making moving toys is a form of dissipation," said Ralph. "It is very fascinating and interesting, but the making of many toys will never make one an expert woodworker. The accuracy and skill required can be developed only by actual constructive work. I suggest that we take up a form of decoration which can be done with the knife.

"There are two ways of making an article in wood pleasing to the eye. One is by varying the outline, as we did in our match scratchers, and the other is by some kind of surface ornamentation. There are many ways of decorating surfaces--carving, pyrography, staining, polishing, etc., and very often several of these methods are combined.

"As we have started to learn the possibilities of knife work, I propose to teach you a form of carving which can be done with the knife alone. Very elaborate work is done with the regular carving tools. This requires a great deal of time and skill, but with the knife alone a wonderful variety of beautiful work can be done even by small boys.

"It is very important to approach it properly, so I am going to give you a few simple exercises and the elaborate designs will come along naturally.

"The work is not new, and evidently grew out of the still older art of notching. Primitive peoples probably saw in it a way to improve the appearance of their various wooden implements. Not only could the edges be notched, but the cutting could be done on flat surfaces as well."

Fig. 54 at _a_ shows one of the earliest designs. It is simply a border of triangular cuts, and while this may be done with the whittling knife, Fig. 55 shows two knives which are better fitted to do accurate work.

The positions for carving are shown in Fig. 56. Hold the knife in an upright position, with the cutting edge away from you, and the point on the apex of the triangle. Press the knife down and then away from you along one of the sides of the triangle. Place it in position again, and repeat the motion along the other side of the triangle, always directly on the line. This brings the deep part of the cut at the apex of the triangle, and it remains to take out the triangular chip. This can be done in either of the two ways shown in Fig. 56, by cutting away from you or toward you. It is well to practise both ways, as in complicated designs the direction of the grain makes it necessary to cut sometimes in one direction, sometimes in another.

The rest of this border is a repetition of the same stroke, and the more elaborate designs are simply different arrangements of triangular cuts.

In Fig 54, _b_ shows two rows of these same shaped cuts, one row inverted, to produce a diamond-shaped border; _c_ shows a border in which the drawing is similar to _b_, but vertical triangles are cut instead of horizontal ones, as this gives a cut across the grain of the wood instead of parallel to it, and is a trifle harder.

Our boys practised on these simple borders for awhile, using knife _a_ and 1/4-inch basswood. The work proved fully as fascinating to Harry as the making of toys, and it was decided that from that time onward the outlines of their woodwork should be simpler, and the decoration should be in the form of chip carving.

While Harry was practising on these simple borders Ralph made the basswood photograph frame shown in Fig. 57, and drew the carving design, as shown, with an H pencil.

To carve this was simply to repeat border _b_. This was so satisfactory that Ralph decided to try his pupil on finer work, and the design shown in Fig. 58 was tried. In each case Harry found that he was making triangular cuts, and removing triangular chips, just as in the first border, only the triangles were in different positions. Ralph suggested that they begin to decorate some of the things they had already made, and the little basswood box shown in Fig. 33 was brought out, and the design shown in Fig. 59 drawn and carved upon it.

There followed a number of "backs," which Ralph explained could be used as thermometer backs, match scratchers, calendars, key racks, and in other ways. In each case, the design was drawn carefully on paper, and thence transferred to the surface of the wood with the same care that it had been done on paper. The designing required considerable thought.

Where a border continued around four sides, the corner became the most difficult and interesting part of the design, and was worked out first. (Fig. 61.)

Very soon the boys found that it was necessary to draw only half the design on paper, and in many cases a corner or quarter sufficed.

The next step was to initiate Harry into the mysteries of curved cutting, a departure from triangular cutting.

He was informed that the cuts were still three-sided, one or two of the sides being but slightly curved.

Fig. 62, used as an enrichment of a "back" in 3/8-inch gum wood, was Harry's first effort in curved chip carving. The edges of the blank piece were bevelled with a plane and Ralph showed his pupil how to do this by holding the blank against a bench hook. The long sides were bevelled first, the ends last, to avoid breaking off the corners.

The key rack (Fig. 63) gave an opportunity to use centre pieces inside a border, diamonds of the flat surface being left uncarved for the placing of the screw hooks.

A pencil box for school followed, the various pieces being shown in Fig. 64. The two sides and ends were made in one strip 1-1/4 inches wide, and afterward cut to length. To secure this strip of uniform width, the shooting board shown in Fig. 65 was used, the plane being laid on its side, giving the 1/4-inch piece of gum wood a perfectly square edge.

Ralph was having his own troubles as a teacher about this time, for he wanted to reserve Harry's education in the use of bench tools until later on, when he should have exhausted the possibilities of the knife; but this method of using the plane was necessary if Harry was to produce blank forms fit for decoration.

The six pieces being squared up, a 1/4-inch margin was left on all sides of the pieces to be carved--the top, front, and two ends.

This 1/4-inch space was for the brads.

The assembling was not done until the carving had been finished, and it consisted of fastening the long sides to the ends with 5/8-inch brads, with a little glue on the end grain of the end pieces. The bottom was put on with brads, and the top hinged to the back by two small nickel-plated hinges. A little hook and eye from the hardware store were put at the front to hold the cover on, and two small cleats were glued to the under side of the cover to keep it from warping.

The time spent on this pencil box was several hours, but the result was a box the like of which could not be bought.

Pencil boxes became the rage with our boys, and although they made several of the same size, in each case the design was different. (Fig. 66.)

XII

CHIP CARVING: CONTINUED

Among the many useful articles which can be made with the knife in thin wood, with carving as enrichment, are the numerous desk accessories, such as envelope holders, letter racks, stamp and pen boxes, pen trays, blotting pads, etc. The boys, after exhausting the subject of pencil boxes for school use, took up the design and construction of letter racks. These, they decided, should be in two compartments for answered and unanswered letters. This called for three uprights, or partitions, and a base. They decided to make them of about uniform dimensions, as shown in the blank form (Fig. 67). The problem of the outline was somewhat affected by the fact that the front was to be carved. This called for a simpler outline than would have been the case had they expected to leave the surface plain. Some of the designs they worked out are shown in Fig. 68.

The form marked _a_ was selected as a beginning, the three partitions cut out exactly alike, and the front piece carved as shown in Fig. 69. The middle partition and back piece were left with plain surfaces.

The cutting of the grooves in the base was a new problem, and Harry was allowed to try his skill with a chisel. The method used was first to make the drawing shown at _a_, Fig. 67. The long side lines of each groove were scored with the point of the knife, going over each line several times, to make the cut as deep as possible. An under cut was then made, as shown in the figure.

The wood in the centre was removed with a 1/4-inch chisel, and the process continued until a uniform depth of 1/4 inch was reached. After all three grooves had been cut, the edges of the base were bevelled with the plane. This bevelling could have been done readily with the knife, but much time was saved by using the plane, always doing the long sides first.

In all the letter racks shown in the illustrations the construction was the same. First, the three blank partitions were made, then finished in their outlines with knife and sand-paper. The carving was always drawn carefully on the surface of the front piece. Third, came the making of the base, and last, the gluing of the partitions into the grooves. To increase the strength of a letter rack, 3/4-inch brads can be driven from the bottom into the partitions, but where this is done it is safer to draw pencil lines on the bottom directly under the centre of each partition. Place the point of the brad exactly on the line before hammering.

Although the forms of the letter rack are endless, the one which our boys found most interesting was based on the ellipse. It called forth a very instructive drawing lesson. Ralph showed Harry first how the figure could be drawn by a string, with two pins to represent the foci of the ellipse. The figure has two dimensions called the major axis and minor axis. (Fig. 70).

The combined length of the two lines drawn from any point on the ellipse to the two foci must always be the same and equal to the length of the major axis. This is readily seen with the two pins and string. (Fig. 71.)

The pencil point as it traverses the ellipse represents any point, and the string remains the same length. Where it is required to draw an ellipse of definite size, say two by three, it becomes necessary to find the foci before the string can be used, and as it requires considerable skill to get the string the exact length, Ralph showed the boy another way, called the trammel method. (Fig. 72.)

Suppose the problem is to construct an ellipse 6 inches × 2-1/2 inches. First draw the two lines _a b_ and _c d_ at right angles, intersecting at the exact centre. Take a straight piece of paper, lay it along _a b_ with one end at _a_. Make a dot on the edge of the paper where the lines cross, and mark it _x_. Next, lay the same strip of paper along _c d_, with the original end at _c_, and again mark a point where the lines cross. Mark this point _y_. At any position of this strip of paper when the points _x_ and _y_ touch the two axes _a b_ and _c d_, the end of the paper strip will be on the ellipse. By shifting this paper trammel and keeping the two points on the axes a series of points may be made at the end of the paper. Connecting this by a pencil line will complete the ellipse. This is a very simple method and a very accurate one.

Our boys drew this figure, 6 × 2-1/2 inches, with a trammel and then worked out the design from it shown in Fig. 73. It made a very satisfactory form for the letter rack, and gave an elliptical space for carving, a new problem in chip carving design.

Two more of these elliptical designs are shown in Fig. 74.

Another feature of this rack was a change in the middle partition; the form is shown at Fig. 75. The making of the base and gluing into the grooves were similar to the earlier designs.

The next design was characterized by an outline composed largely of straight lines.

The middle partition was lower than the front and back pieces, as shown in Fig. 75.

The boys found a great deal of pleasure in working out a decorative scheme for the carving. Having discovered how easy it is to carve the long flowing curves, they introduced them wherever possible. The general shape of the carved section must of course conform to the outline of the wood, but while filling in these flowing curves they soon learned to sketch them in free-hand.

To a person who has not tried this work or who has not begun with simple cuts it appears very difficult, but when it is remembered that only one cut can be made at a time and that each chip is a triangle, even if its sides are slightly curved, it actually proves very easy, and within the power of any normal boy to accomplish.

Harry was introduced at this time to the use of the veining tool, a fine gouge with a cross section almost V-shaped. This was used to emphasize the outlines of the designs by simply pushing ahead directly on the lines. When veining straight lines, it may be guided by a ruler or other straight edge, but for curves, a free-hand movement is necessary. A very good practice piece is the design shown at Fig. 76. This may be applied to the front of the letter rack design. (Fig. 69.)

The pen-holder shown at Fig. 77 is one of a large number which were made by the boys. The pieces were cut out with a knife to the blank forms shown. On all pieces like these, afterward to be assembled, the edges were made straight and square on the shooting board, and the carving done before assembling. This pen-holder was put together with 3/4-inch brads with the exception of the front, which was glued, as it was thought best not to have nails showing on this important side. (Fig. 78.)

XIII

CHIP CARVING AND KNIFE WORK (See 31, 109)

"I like this new work better than anything we have ever done," said Harry one day when he and Ralph were up to their ears in carving, whittling, and designing.

Ralph smiled as he remembered Harry's intense interest in making moving toys. "As I told you once before," he replied, "this is not new but old. The people of northern Europe have done it for centuries, and the reason is not hard to find. In Norway during the long winter it gets dark very early, in some places at three o'clock in the afternoon, and does not become light again until nine o'clock in the morning. The result is very, very long evenings, when it is much more comfortable to work indoors.

"At an early era the people developed this beautiful art of carving, and spent their long evenings in working at it. They became very skilful and as most of the household utensils were of wood, it was not at all unusual to see the household furniture, even to their bread boards, beautifully carved."

"By the way," said Harry, "can't I make a paper knife now? You know you said I could after I had learned to use the knife!"

"Yes, I think you might try your skill on something of that character now. It will be quite a change from this flat work we have been doing. It will require a harder wood, however, than you have been using, as a paper knife must be thin and strong at the same time.

"The Swedish carvers use apple wood a great deal for their paper knives, but as this is rare with us, suppose we try rock maple. It is white in colour, close grained, and hard."

As usual, they worked up their design on paper first and sketched in the carving shown in Fig. 79.

A piece of rock or sugar maple was first squared up and laid out in pencil as shown at _B_. In order to get the outline to conform exactly to the drawing, the form was cut out of paper and traced on the face of the wood. The blank form was then whittled out to the pencil line, and sand-papered smooth as shown at _c_.

Maple proved to be a hard wood to whittle.

Notches were cut at _d d_ after drawing the edge view on front and back edges. The blade and handle were then whittled down to lines _e_ and _f_.

"Whew!" exclaimed Harry, "don't ever give me any maple to whittle again."

"Well, you wanted to make a paper knife, didn't you? A paper knife that would break when it fell on the floor wouldn't be of much use, and you are not through yet. The blade must be cut down to a fairly sharp edge on both sides now."

This was done by bevelling the edges as shown in _h_ and the bevel gradually cut back to the centre line, as shown at _i_ and _j_. Harry concluded that this was the hardest work that he had ever done.

"Now you understand," said Ralph, "why I couldn't allow you to make a knife at first. All the training I have given you was necessary before you had the requisite skill and control of your hands. The carving will be easy for you because of all this practice. Skill is something which comes that way. Why, if I should give you the problem of making that first key rack over again, you would do it in about one third of the time, and very much better than at your first attempt. You have been gaining skill without knowing it.

"Just to show you how much you have advanced, I will give you one or two key rack designs to be decorated with chip carving. When they are finished, take them into the house and compare them with the first you made. I think you will be amused at the difference. That original piece of which you were so proud will seem a very crude affair now."

"All right," said Harry, "but I should like to make one more paper knife first if you don't mind."

"Very well; make up a new design, because no artist ever duplicates his work," said Ralph with a mischievous smile.

The smile was premature, however. The boy had not been designing woodwork for nothing. The design is shown at No. 2, Fig. 79, and even Ralph, severe critic though he was, had to admit that it was "pretty fair."

"Looks like a table knife," he said seriously. "However, it is your own design, so go ahead and make it. Try a piece of cherry this time. It makes a good wood for carving, and is not quite so hard to whittle as maple."

The different steps in the process of cutting this out were the same as in No. 1, Fig. 79.

The key rack shown in Fig. 80 was comparatively easy after making paper knives. The bevelling of the curves at the ends was the only new feature of the knife work.

The making of presents went rapidly onward from this time. The next article to engage our woodworkers' attention was the blotting pad, made of two pieces of black walnut fastened together with the screw handle. (Fig. 81.) The blotter is bent around the curved face of the lower part, and the ends gripped between the two parts by tightening the screw. These handles with screw attached are of brass, and can be obtained at any hardware store.