“Grizzly Giant,” a Big Tree in Mariposa Grove, California

ELEMENTARY WOODWORKING

BY
EDWIN W. FOSTER

GINN & COMPANY
BOSTON · NEW YORK · CHICAGO · LONDON

Copyright, 1903
By EDWIN W. FOSTER

ALL RIGHTS RESERVED

25.1

The Athenæum Press
GINN & COMPANY · CAMBRIDGE
· MASSACHUSETTS

PREFACE

This text has been prepared for the purpose of furnishing the pupil with the essential facts about tools and their uses. However efficient the instruction may be and however attentive the pupil, it is impossible for him to fully grasp and comprehend during a demonstration the names of tools and technical terms, most of which are new to him. This applies with equal force to the manner of using the tools and to the methods of working.

The function of the text is to supplement the instruction of the teacher. It is intended to gather up and arrange in a logical order the facts which the pupil has already been told. By this means these facts will become fixed in the mind of the pupil and he will work with a better understanding and make greater progress.

It is believed that the text can be used to the greatest advantage by requiring the pupil to read up the subjects presented in class immediately after the close of the lesson. Frequent rapid reviews and occasional written tests are very effective.

No course of study in the form of a series of models is presented. It is hardly possible for any two schools to follow the same series of models. Local conditions necessarily affect the choice of a course, while new and better designs are being brought out continuously.

The order in which the tools are described in the following pages is the one that has seemed most natural. They may be taken up, however, in any convenient and logical order.

It is with the earnest hope that nature study and manual work may be closely correlated, that Part II is added. No better period can be selected in which to study trees, their leaves, bark, wood, etc., than when the student is working with wood, learning by experience its grain, hardness, color, and value in the arts.

Occasional talks on the broader topics of forestry, its economic aspects, climatic effects, influence on rainfall, the flow of rivers, floods, droughts, etc., will be found interesting as well as instructive, and such interest should be instilled into every American boy and girl.

The writer is indebted to the Fish, Forest, and Game Commission of New York state for the series of Adirondack lumbering scenes, and to the United States Bureau of Forestry for the views of California Big Trees.

EDWIN W. FOSTER.

CONTENTS

ELEMENTARY WOODWORKING
Part I

CHAPTER I
INTRODUCTION

In order to obtain good results in the using of tools it is necessary to know their construction, how to properly sharpen and adjust them, and the correct method of handling them. It is also essential to know how to lay out and work the material or stock. Carelessness or a lack of knowledge is invariably followed by a failure. It is more important at first to work carefully and accurately than rapidly.

“Tools are made to be used, not abused.” They must be kept clean and sharp and should be used only for the purpose intended. Wipe them off occasionally with an oily rag or waste to prevent them from rusting. Put away all tools not in use and keep the top of the bench clean. Do not mark it with a pencil or scratch it with a knife. Do not cut into it with the chisel or allow other tools to mark or deface it. When using glue, shellac, or similar materials, cover the top of the bench; or, better still, do the work on a table provided for that purpose.

The plan of work in making all models is in general the same and is as follows:

First. “Squaring up” the stock.

Second. “Laying out” the work.

Third. Cutting to the lines.

When the article is composed of two or more pieces a fourth step may be added, namely, fitting and securing the parts.

The tools used may be divided into three groups, as follows:

First. Laying-out tools. These include the rule, try-square, marking gauge, bevel, and knife.

Second. Cutting tools. In this group are the saw, plane, chisel, spokeshave, bit, and knife.

Third. Miscellaneous tools, such as the hammer, mallet, screw-driver, brace (or bitstock), and others not so common.

CHAPTER II
MEASURING AND MARKING TOOLS

1. The Rule. The standard unit of length is the yard, but the foot is commonly used for all measurements in woodwork. If the rule be twelve inches long it is known as a foot rule, and if twenty-four inches long it is called a two-foot rule. The inches are subdivided into halves, quarters, eighths, and in some cases sixteenths. Rules are usually of boxwood or maple, with brass joints, and are commonly made to fold once or twice.

Fig. 1. The Rule

The rule is quite thick, and if laid flat upon the work to be measured errors will usually follow. It should be stood on edge so that the pencil or knife point may touch the divisions on it and the wood at the same time. The proper position when laying out measurements is shown in the sketch ([Fig. 2]). Consecutive measurements should be laid off without moving the rule.

Fig. 2. Methods of using the Rule: A, incorrect; B, correct

2. The Try-Square. The try-square has two distinct uses: first, to act as a guide for the pencil or knife point in laying out lines across the grain at right angles to the edge, as shown in [Fig. 4]; second, for testing or trying the adjoining sides to see if they are square with each other.

Fig. 3. The Try-Square

The try-square may be made entirely of iron or steel, but sometimes the beam A is of wood with a brass strip C to protect it and to take the wear. The blade B is of steel and is divided, like a rule, into inches and fractions of an inch. Try-squares are made in several sizes, the most convenient for general use being six inches.

Fig. 4. Methods of using the Try-Square

In using the try-square the beam should be held firmly against the face or edge of the stock. When working near the end of the piece, if the beam projects, reverse its position. For nice, accurate work the knife point instead of the pencil should be used for lining.

When it is desired to saw off the end of the stock it is first necessary to mark or square clear around it with the knife and try-square. In doing this the beam of the try-square must be used against the work face and joint edge only. Large squares made of steel in one piece are called framing squares, and are used by carpenters and others for rough or large work.

Fig. 5. The Framing Square

Fig. 6. The Marking Gauge

3. The Marking Gauge. The marking gauge is shown in Figs. [6] and [7]. A is the gauge stick, B the gauge block, S the set screw, and P the marking point, or spur. The gauge stick is graduated like a rule into inches and fractions, beginning at the steel marking point; but as the latter is not always exactly in the right place the graduations are not entirely reliable. It is safer then to set the gauge with the rule in the manner shown in [Fig. 7].

Hold gauge bottom side up in left hand and rule in right. Place end of rule against gauge block and the measurement desired at spur. Turn set screw. The gauge is then accurately set. In the cut the gauge is set at one inch and is ready for use.

Fig. 7. Setting the Marking Gauge

To gauge a line parallel to the edge of a block hold the tool firmly, with thumb and forefinger encircling gauge block. Tip the tool away from you until the marking point (spur) barely touches the wood and push the tool away from (never toward) you. The line made should be as fine as a knife line. A little practice is needed to give the proper control, as the marking point tends to follow the grain of the wood, which is usually not straight.

Fig. 8. Holding the Marking Gauge

A good plan is to use a small piece of prepared stock as a practice block, laying out lines a quarter of an inch apart, then an eighth, and finally a sixteenth.

4. The Bevel. The bevel differs from the try-square in having a movable blade.

Fig. 9. The Bevel

This tool may be used to lay out lines at any angle from zero to 180 degrees. The blade may be fixed firmly at any desired angle by simply turning the set screw. The method of using it is similar to that of the try-square.

CHAPTER III
CUTTING TOOLS

5. Saws. The saw might be described as a succession of chisels, one back of the other. We can readily understand the action of the saw by making cuts with a narrow chisel along the grain of a piece of wood, as shown in [Fig. 10] at a.

Fig. 10. Cutting with and across the Grain with a Narrow Chisel

The little pieces of wood removed in this way are similar to the sawdust made by the saw, the only difference being that in the saw the teeth are narrower and the little pieces consequently smaller, and instead of one chisel dozens are being pushed forward at one time.

A saw with these chisel-shaped teeth, and used for cutting along the grain, is called a ripsaw.

That this tool will not cut so readily across the grain may easily be proved by again resorting to the narrow chisel and attempting to repeat the first experiment. The wood will act as shown in [Fig. 10] at b, splitting along the grain in both directions. It is quite evident, then, that a tool for cutting across the grain must be constructed in some other way.

Fig. 11. The Saw

Continuing this experiment, let us cut the fibers with a knife point in two parallel lines across the grain, close together, as at c. It will be found that the wood between these lines may now be easily removed with the narrow chisel. This fact is made the basis on which we construct the crosscut saw. Every tooth is sharpened to a point, one on the right side, the next on the left, giving two parallel lines of sharp points designed to cut the fibers, as was done in our experiment with the knife. [Fig. 12] shows the end view of the crosscut teeth enlarged. Observe that not only are the alternate teeth sharpened on opposite sides, but each tooth is bent outward from the body of the saw. This bending is called set, and is designed to make the saw cut, or kerf, wider than the thickness of the saw, that the latter may pass easily through the wood after the teeth have done their work. If it were not for this set, the fibers would spring back against the body of the saw after the teeth had passed and make the work very laborious. When a saw is properly set it should pass through the wood easily.

Fig. 12. Teeth of Crosscut Saw

Fig. 13. Teeth of Ripsaw

The teeth of the ripsaw are also set, but, as will be seen in the sketch, the bottoms are flat like a chisel instead of pointed like those of the crosscut teeth.

Beside the end views of the two kinds of teeth, the side views, which are also different, are shown in Figs. [12] and [13].

We are inclined to think of the saw as a very commonplace article, yet a careful examination will prove that the greatest care and skill are needed in its manufacture. Observe that the body, which must be of the best steel, tapers, being considerably wider at the handle than at the opposite end. This is to give strength, and to prevent buckling, or bending, as the tool is pushed forward.

Fig. 14. Body of Saw, showing Tapers

Most delicate measurements must be made, however, to discover that not only the width but the thickness increases from A to B, and decreases from C to D. How carefully this tapering must be done can be realized when we know that the difference in thickness from A to B is only three one-thousandths of an inch, and from C to D twelve one-thousandths at end A and five one-thousandths at end B.

Fig. 15. Method of holding the Saw

The saw should be held in the right hand, with the left grasping the board. The thumb of the left hand acts as guide, the saw is tilted, as shown in [Fig. 15], and drawn toward the worker at the first stroke. This tool should be used without exerting much pressure, in accordance with the general rule that we do our best work with tools when we work easily and deliberately.

Fig. 16. The Backsaw

Many varieties of saws are designed for special purposes, including those which cut stone and metal.

Fig. 17. Method of using the Backsaw and Bench Hook

6. Backsaw. The backsaw is a crosscut saw with small teeth, and has a heavy steel backpiece, [Fig. 17], to prevent bending. In this respect it differs from the ordinary crosscut varieties, which bend readily. The purpose of the backsaw is to make fine, straight cuts in delicate, accurate work. The steel back B is necessary on account of the thin blade, but on account of the thickness of B no cut can be made deeper than the line C. This tool will cut in any direction with reference to the grain, but is primarily a crosscut saw.

Fig. 18. The Bench Hook

Fig. 19. The Turning Saw

7. The Turning Saw. In ordinary work the saw is supposed to cut to a straight line, but there are certain classes of work where it is desirable to follow a curved line, and consequently a special tool is necessary. The turning saw shown in the cut is used for this purpose. The handles holding the saw blade may be turned in any direction with reference to the frame.

8. The Plane. The plane reduces our rough lumber to planed, or dressed, stock. The cutting part is a thin, wide chisel called the plane iron.

Fig. 20. The Plane Iron in Action

[Fig. 20] shows the position of the plane iron in operation. Assume the iron to be moving in the direction of the arrow on a piece of wood. The sharp point would enter the board and, should the grain be unfavorable, start a splitting action, as shown at a.

We wish to smooth the wood instead of roughing it, and must in some way stop the splitting. This is accomplished by placing a cap iron on the plane iron, as shown at b. The cap bends and breaks the shaving before the splitting action has a chance to begin, and gives the spiral form so familiar in wood shavings.

Fig. 21. Plane Iron, Cap, and Set Screw

The cap is firmly fastened to the plane iron by a stout screw, and this whole combination is fastened in the throat of the plane by a clamp ([Fig. 22]). The opening on the bottom of the plane through which the cutting edge protrudes is called the mouth of the plane.

Fig. 22. Sectional Views of Iron Plane

9. Adjustment of Plane. There are two ways of adjusting a modern iron plane,—by means of the set screw s, and of the lever l.

Screw s lowers or raises the plane iron so that we may take a thin or thick shaving, and lever l straightens the iron, which is liable to project more on one side than on the other, and will then take a shaving thicker on one side than on the other.

Before using the plane always examine it carefully. Invert the tool, holding it toward the light with the toe toward you, and glance along the bottom. If the iron projects, observe whether it is even, and if not, move the lever until it is. For a thin shaving the cutting edge should appear as a black line of uniform thickness. For a heavy shaving turn the brass screw until the iron projects slightly.

In using the plane avoid a stooping position. Stand with the right side to the bench and with the shoulders thrown back. Let the pressure of the left hand be greater at the beginning and that of the right hand at the end of the stroke. The tool should rest perfectly flat on the wood from start to finish.

Fig. 23. Irons of Smooth and Jack Planes

10. The Jack Plane. The ordinary plane iron has a straight edge, as shown at a, [Fig. 23], but when a large quantity of wood is to be removed the iron is sharpened in the shape shown at b. This curved iron will cut out the wood in hollows, leaving ridges between, and it is necessary to follow this jack plane with a finer one having a straight edge in order to smooth the surface. The jack plane might be called a roughing plane.

Fig. 24. Relative Sizes of Smooth and Jack Planes

The lower figure is a jack plane

11. The Smooth Plane. The smoothing plane is shorter than the jack plane, its object being to smooth the surface without regard to straightening it, as it is supposed that the straightening has previously been done. The cap iron in the smooth plane should be set from a sixteenth to a thirty-second of an inch from the cutting edge of the plane iron.

Fig. 25. Action of Short and Long Planes

12. Jointers. For straightening very rough and uneven stock a long plane is necessary ([Fig. 25]). In the illustration let line ab represent the edge of a very uneven board. A short plane c would simply follow the hills and hollows, smoothing but not straightening it, while a long plane, as shown at d, would merely cut off the top of the high places, as shown by the dotted line, and would not touch the bottoms of the hollows until all the elevations were leveled; in other words, until the surface was straightened. Such planes, which are often three feet long or more, are called jointers.

Fig. 26. The Block Plane

13. The Block Plane. To square the end of a piece of stock the conditions are quite different from those just described where we were planing with the grain. In end planing no cap iron is necessary, the plane iron in the block plane being reversed with bevel side up.

This tool requires more care than the others, as the stroke is usually quite short, and if the cutting edge is allowed to reach the farther corner, the latter will be broken off.

Fig. 27. Method of using Block Plane

To avoid this error the plane must be lifted up before the end of the stroke, as shown by the dotted line a. The piece is then reversed, and planed as shown by arrow b. In this way the whole end is smoothed, without ruining the corners.

Besides these standard planes there are many patent and special ones for cutting tongues, grooves, beads, etc.

14. The Wooden Plane. Although the iron-bodied planes just described are now in common use, the old-fashioned wooden plane is still the favorite of many woodworkers.

Fig. 28. The Wooden Plane

This tool, while lacking some of the adjustments of the iron plane, was much simpler and contained a smaller number of parts.

The iron and cap were held in position by a wooden wedge, which was driven in by a light blow of the hammer. The workman removed the iron and wedge by turning the plane upside down and striking the forward part a light downward blow on the bench, while the thickness of the shaving was increased by a light tap on the plane iron.

One of the chief objections to the wooden plane was its liability to wear and warp, so that it became necessary to straighten, or joint, the face. No such difficulty is encountered in the iron-bodied plane.

15. The Chisel. The chisel is one of the simplest forms of cutting tools. The size of the angle a depends on the kind of material to be cut.

Fig. 29. Cutting Angle of Chisel

A chisel for cutting wood must be sharpened to an angle of from 30 to 35 degrees.

By careless sharpening an extra bevel is sometimes formed, as shown at b.

The cutting angle is then no sharper than if the chisel were shaped like that shown by dotted lines, and care must always be taken when sharpening to keep the line cd straight, so that angle a will be the real cutting angle.

Two classes of chisels are in common use: the framing chisel used for heavy work, such as the frames of buildings; and the firmer chisel. The framing chisel is strong and heavy, and has a handle capable of withstanding the blows of a mallet. The firmer chisel is designed for finer and lighter work without the mallet.

Fig. 30. The Framing Chisel

Fig. 31. The Firmer Chisel

Fig. 32. Proper Position for Horizontal Chiseling

The chisel must be sharp if we wish to do good and accurate work, and a cut on the hand made by such a sharp tool is liable to be a deep one. Special care must be used in handling it, keeping both hands away from the cutting edge, as shown in the sketch, and placing it when not in use where it cannot be pushed off the bench on to the floor or the student’s feet.

[Fig. 32] shows the method of using the tool on horizontal work, and [Fig. 33] for vertical cutting. For this kind of work only a small portion of the cutting edge can be used, the student judging for himself how heavy a cut to take by the hardness of the wood and amount of strength required. Good work can never be done when one has to exert all his strength on the tool. The best results are obtained when we work easily.

Fig. 33. Proper Position for Vertical Chiseling

Better work can usually be done with the chisel if, instead of pushing it straight ahead or straight downward, we incline it somewhat so as to secure a slight paring action.

Fig. 34. Sharpening Chisel on Oilstone

When the chisel becomes dull, unless its edge has been nicked or ruined by some accident, it is only necessary to sharpen it on the oilstone. Hold the tool with the bevel flat on the stone. A drop or two of oil may be used to lubricate the stone, the tool being worked back and forth on the face of it. Especial care must be taken to avoid a rocking motion, which will produce a curved edge instead of a flat one.

Fig. 35. Common Forms of the Brace

After the rubbing, reverse the chisel, lay the flat side firmly on the stone, and draw toward you. This is to straighten the wire edge which has been turned over by the rubbing. The wire edge may then be removed by drawing the cutting edge across the end of a block of wood. When the chisel is nicked or very dull it must be ground on the grindstone.

16. Brace and Bit. The old-fashioned augers and gimlets have given way to the modern brace and bit.

Fig. 36. The Center Bit

The brace, which is sometimes called the bitstock, allows both hands to be used continuously, which was not true of the old-fashioned auger. Several varieties of the brace are in use, the ones shown in the cuts being common.

Bits are designed for a variety of purposes, the name being applied to a tool which is to be turned by the brace. The old-fashioned center bit shown in the cut possessed most of the essentials of a good boring tool.

Fig. 37. The Auger Bit

The sharp spur in the center allowed the hole to be accurately placed. The lip on the outer edge cut the fibers in a circle before the chisel edge began to remove the wood, and so a smooth hole could be bored; but considerable pressure was necessary to force the tool through the wood.

The progress that has been made in the manufacture of tools can be easily appreciated by comparing this center bit with the modern auger bit.

Referring to the sketch ([Fig. 38]), B B are two knife points, or nibs, which cut the wood fibers before the chisel edges, or lips, C C, can touch the wood. The point A allows us to accurately place the center of the hole where we wish it, and the screw back of A draws the tool into the wood as it revolves. This part is known as the spur, or worm. On this class of bits no pressure is necessary.

Fig. 38. Details of Auger Bit

The opposite end of the bit, called the shank, fits into the brace. Any tool with such a shank, and designed for use with the brace, is a bit. We have screw-driver bits, gimlet bits, auger bits, etc.

On the shank of an auger bit will be found a number. This is the numerator of a fraction whose denominator is 16. If we find this number to be 4, it is a ⁴⁄₁₆, or a ¼-inch bit. If the number is 16, we have a ¹⁶⁄₁₆, or a one-inch bit, etc., always referring to the diameter of the hole which the tool will bore.

In using the brace and bit care must be taken to see that the bit shank is far enough in the brace to be fastened securely, and that the tool is held at right angles to the wood. It may appear from the front to be perfectly vertical, yet by stepping to one side and looking at it from another position it will frequently be found far from vertical. When starting a hole it is well to do this several times until assured that the tool is working in a true upright position.

Fig. 39. The Gimlet Bit

Fig. 40. The Countersink Bit

The gimlet bit is used for small holes, such as we make for screws. In this case the hole must be countersunk to receive the screw head, when flat-headed screws are used. The countersink bit is shown in the cut, and its purpose is more fully explained in the chapter on screws.

17. The Spokeshave. The spokeshave is practically a short plane with handles at the side so that the tool may be drawn or pushed. It may be adjusted by means of screws to take light or heavy shavings, and is used principally to smooth curved surfaces. The forming of a hammer handle is a good illustration of the kind of work it will do. It may be worked toward or away from the worker, and is an exceedingly handy tool.

Fig. 41. The Iron Spokeshave

CHAPTER IV
MISCELLANEOUS TOOLS AND METHODS OF WORK

18. Hammer. The carpenter’s hammer is used principally to drive or withdraw nails.

The various trades have hammers made specially for their needs; thus we have machinists’, roofers’, upholsterers’, stonecutters’, and other hammers, but the claw hammer shown in the sketch is the one commonly used by workers in wood.

Fig. 42. The Claw Hammer

The head a ([Fig. 43]) is of steel, with the face b specially hardened so that it may not be dented by the nails. Notice the length of the handle h. This length did not simply happen. Had it been intended to hold the tool in the position shown at A, the handle would not have been made so long. The proper position is that shown at B. Position A is frequently taken by beginners, and should be studiously avoided.

Fig. 43. Using the Hammer

A nail may be withdrawn with the claw, and be kept straight for further use by a little care. Having started the nail slightly, place a small block of wood under the hammer head, as shown at C. Should the nail be an unusually long one, the size of the block may be increased as the nail comes out.

Fig. 44. Common Forms of Nail Punch, or “Set”

In driving nails care must always be taken not to mar the surface of the wood by striking the nail head after it has become even with the surface, as this produces a depression and ruins any fine surface.

If it is desirable to sink the nail head below the surface, a nail punch, or set, is used. This is always necessary when the surface is to be planed after the nailing.

19. The Mallet. The mallet might be described as a hammer with a wooden head, and is used whenever we wish to deliver a blow which shall be less concentrated than that of the hammer. It is used in certain kinds of heavy chiseling, such as house framing, and gives a blow which does not shatter the tool handle as a hammer would.

Fig. 45. The Mallet

The use of the mallet is well illustrated by the making of a mortise-and-tenon joint, the chisel and mallet being used to cut the opening known as the mortise, as shown in [Fig. 46].

20. Screw-Driver. The screw-driver is perhaps the most common of household tools, and is probably abused more than any other. The handle is usually flattened so that the hand may grip it more tightly, but occasionally a round or fluted handle is seen.

Patent spiral screw-drivers have come into use in recent years, but where considerable force is required the brace and screw-driver bit are more effective.

Fig. 46. Cutting a Mortise

21. Sandpaper. “Sandpaper is the last resort of a poor workman.” This statement has been made by many teachers to many thousands of students, and is true in many cases; but there are certain kinds of work where sandpaper, if properly used, is allowable.

Fig. 47. The Screw-Driver

It must always be kept in mind that a surface which has been sandpapered has become “gritty,” i.e. the fine sand has come off and is more or less imbedded in the wood. Consequently sandpapering must not be done until all tool work has been finished, as the grit will take the edge off the best tool, and the finer the edge the more quickly will it be ruined.

Fig. 48. An Exercise involving the Use of Sandpaper

Again, a sandpapered surface is always a scratched surface, and the finest of scratched surfaces cannot compare with the perfectly smooth, satiny surface produced by a sharp plane. However, there are many places where neither the plane nor spokeshave can be used, and here it is allowable to use sandpaper after the tool work has been carried as far as practicable.

[Fig. 48] is a case where sandpaper may be used with propriety. The bevels in this lesson are to be chiseled and then sandpapered with a sandpaper block,—the block in this case being simply a small piece of wood with square edges, about which the sandpaper is fastened closely.

Curved articles, such as the hammer handle, must dispense with the block, the sandpaper being held in the hand.

22. Squaring up Stock. This term simply means to reduce a piece of sawed or rough lumber to one having smooth, flat sides at right angles to each other, and of definite length, breadth, and thickness (see [Fig. 49]).

Fig. 49. The Successive Steps in squaring up Stock

First. Straighten one face with fore plane, jack plane, or jointer, and smooth with smoothing plane. This face, called the working face, becomes the basis from which all the other sides are squared.

Second. Plane one of the adjoining edges and make square with the working face. This edge, known as the joint edge, must be thoroughly tested throughout its entire length with the try-square, and must be square with the working face at every point.

Third. Set marking gauge at required width and with gauge block against the joint edge, gauge a fine line on working face.

Fourth. Plane down second edge to gauge line, just drawn, squaring the edge with working face.

Fifth. Set gauge to required thickness and gauge line on both edges from working face.

Sixth. Plane face parallel to working face down to the two gauge lines. This gives the required thickness. It only remains now to secure the required length.

Seventh. Square knife line around the four smoothed sides with knife and try-square as near one end as possible, carefully observing the precautions given in Chapter II.

Eighth. From the line just drawn, measure the required length along edge of working face and square a line on the four sides at the last point, as at first end.

Ninth. Block-plane first end to knife lines. If the second line is more than an eighth of an inch from the end of block, saw to the knife line with backsaw, and block-plane smooth and square.

The above method should always be followed in preparing stock for laying out the exercise.

23. Laying Out. Let it be assumed that the exercise to be executed is the middle lap joint shown at A, [Fig. 50].

Fig. 50. Successive Steps in laying out and making a Middle Lap Joint

First. Square up stock, leaving ends rough.

Second. Lay off the length of each piece, in this case 4½ inches, with an eighth of an inch between for sawing, as at a.

Third. Square all the lines around four sides.

Fourth. Saw to end lines and block-plane ends.

Fifth. Lay off width of opening in piece No. 1 and square lines across face and halfway down on both edges.

Sixth. Measure length of lap on No. 2, square the line across bottom and halfway up the sides. Gauge the horizontal lines ll from working face.

Seventh. Saw pieces No. 1 and No. 2 apart and block-plane ends.

Eighth. Saw to the lines, chisel, and fit the pieces.

Although the above is the method of laying out a typical joint, each problem will require special treatment and here the student will be guided by his instructor.

24. Securing Parts. Many articles made of wood consist of several pieces fastened together.

When two pieces are fitted together the surfaces of contact are called a joint. There are many kinds and shapes in joinery, and usually some extra fastening is required to hold the pieces together. These aids are glue, nails, and screws; while on heavy construction still others, such as wedges, pins, and dowels are used. The first three are commonly used in small work.

Fig. 51. The Hand Screw

Glue is of two kinds, fish and animal. Both are made from refuse matter,—animal glue being manufactured from such products as bone, horn, hoofs, and hide.

The dry glue in the form of chips must be dissolved in water and heated, being applied while hot. Liquid glues sold in cans ready for use are now very common and require no heating.

In making a glued joint it is usually necessary to hold the pieces tightly together until the glue has set, or hardened, and as this takes some time, hand screws built on the principle of the vise are resorted to. [Fig. 52] shows two pieces glued together and fastened in a pair of hand screws. Care must always be taken to keep the jaws of the latter parallel. At a this is shown done properly, while at b is shown a careless method which, of course, will spoil the joint.

Fig. 52. Method of using the Hand Screw

In gluing on the end grain a preliminary, or sizing, coat of glue must first be made to fill up the pores, which act very much like a sponge. This coat should be allowed to dry, or partially dry, before applying the final coat; otherwise the pieces will be held weakly, if at all. Beginners are inclined to use too large a quantity, and this tendency should be avoided.

In some cases nails are used together with the glue, as at the corners of picture frames. It is customary in this instance to nail in only one direction, as shown in [Fig. 53].

Fig. 53. Miter Joint at Corner of Picture Frame

25. Nails. The nails in common use are of two kinds, cut and wire.

Two views of a cut nail are shown in [Fig. 54], a being the side view and b the front view. Notice that in the front view the sides converge like a wedge, while in the side view they are parallel.

Fig. 54. Use of Cut Nails

Care must always be taken that the point does not enter the wood as shown at c, as the wood will be split by the wedge action; d shows the proper method.

Steel wire nails are now in general use. They are made from wire and are consequently round in section, with a comparatively sharp point. There are two distinct kinds, named flat head and bung head.

Flat-head wire nails, as the name implies, have thin, flat heads, which prevent the nail from being driven beneath the surface.

Bung-head wire nails, or brads as the smaller sizes are called, have very small heads, which allow the nail to be sunk below the surface. This is done by means of the nail punch, or set, and is necessary when the surface is to be planed after the nailing.

26. Screws. Screws are much used, and allow the pieces to be readily taken apart. They are divided into two classes, flat head and round head, and are of steel or brass. Steel screws are either blued or bright. Bright screws are polished and blued screws are produced by treating the bright ones with heat or an acid.

Fig. 55. Methods of using Screws

[Fig. 55] shows a flat-head screw at a and a round-head at b. Flat heads are used for the more common work where it is desirable to have the screw head flush (even) with the surface or below it, while round heads are used where this is not necessary. In the latter case round heads are used partly because they are more ornamental. Flat heads must always be flush or below the surface, and in all but the softest woods it is necessary not only to bore a hole for the screw, but also to countersink it with a countersink bit in order that it may receive the head. Two methods of fastening with flat-head screws are shown in [Fig. 55].

Sketch A shows the two pieces of wood in position, the hole bored in upper piece (only) and countersunk; B shows the screw in position. In this case the screw head is visible. It is occasionally desirable to hide the screw entirely. Sketch C shows the hole prepared for the screw; D shows the screw in position and a circular wooden plug driven in over it. The plug is then leveled with the surface and the screw completely hidden.

Fig. 56. The Difference between Perspective and Mechanical Drawing

27. Mechanical Drawing. A mechanical, or working, drawing is quite different from a pictorial drawing such as an artist produces. The artist’s drawing represents objects as they appear, while the mechanical drawing represents them as they really are. Things in nature do not look as they are. For example, when we stand on a railroad track the rails appear to converge until they seem to meet in the distance. We know that this is not the case, that the rails are really everywhere equally distant. The optical illusion of the rails meeting at the horizon is called perspective. Mechanical, or constructive, drawing takes no account of perspective. In [Fig. 56] a is the perspective representation of a track, while b shows a track by mechanical drawing.

In a working drawing more than one view is necessary to show the true shape of an object.