Chapter IX: Preface (9)

The uprights should be mortised through the base board, and the cross piece at top halved to the uprights. The sloping board with weights fastened to it has a generous-sized hole fitted loosely over a dowel at the right-hand end of bottom board. A groove cut in the latter allows the weighted board to fit tightly when it falls, the dowel with bait dropping into the groove.

Fig. 225 at _c_ shows a snare frequently used. It should be placed in front of a hollow log, box, or barrel, so that the animal must put his head through the loop of wire in order to reach the bait.

The first pull at the end of the trigger releases the spindle, and the bent sapling does the rest. The loop of wire should be held open and in position by twigs conveniently placed.

The killing of our few remaining wild creatures, however, should never be done for sport. It is excusable only when they become destructive or troublesome. Squirrels, rabbits, and chipmunks are much more interesting as friends than as caged or killed victims.

XLVIII

OUTDOOR CARPENTRY

Outdoor construction or carpentry, as distinguished from the indoor work of the cabinet maker, calls for a general acquaintance with tools, some mathematics, an elementary knowledge of the strength of materials, and a good supply of common sense. It demands also some knowledge of the effects of frost on foundations, and requires judgment in providing for the elements, wind, rain, snow, and sun.

Every building may be resolved into certain parts, such as foundations, framing, roof, door, and window frames, outside covering or siding, flooring, partitions, doors and windows, wall covering or ceiling, interior finish, hardware, etc. These will be taken up in their order.

FOUNDATIONS

These, like all details, depend on the size and purpose of the building. The method of setting a small building on posts has been explained under poultry house, and sheltered seat for tennis court. It should be used only for small structures, such as camp buildings, sea-shore cottages, and out-buildings. Brick, stone, and concrete all have their advantages, but for young builders, concrete is perhaps the best and easiest to handle. The woodwork necessary for concrete work is extremely important, and its possibilities have hardly been touched, even to-day. The box or form should present the smooth side of the boards to the concrete, and should be so constructed that the form may be readily removed after the concrete has hardened. This sounds like a simple matter, but it becomes complicated in many cases. The method of fastening the wooden frame to a concrete foundation is suggested in the chapter on the making of a pergola. In some houses the frame is simply laid on the concrete, and the weight of the building is trusted to keep it in place.

In the case of small structures this would not be sufficient, and a better way would be to imbed bolts in the cement before it hardens. Pass these bolts through holes bored in the sill, and fasten them with nut and washer on top, after the concrete has hardened.

Any foundation should be sunk at least three feet in the ground, otherwise it will be "heaved" by the frost. Where a cellar is to be built, the foundation should be of sufficient depth to leave at least 6 feet 6 inches in the clear between floor of cellar and under side of floor beams, and seven feet would be better. If the foundation extends two feet above the ground, its bottom would be 5 feet 6 inches below the ground level.

The thickness of the concrete wall must depend on the size and weight of the building, and for a small cottage it should not be less than ten inches. The columns described for the pergola make an excellent foundation for a small building to be placed on posts, as they do not decay and are permanent. They may be used to advantage for porches in place of wooden posts.

After a building is completed, some of the top soil removed in digging the cellar should be graded up to the foundation at a slight slope, to shed the rain and carry it away from the building. The box for a concrete wall should be well supported and braced, as the weight is sufficient to force the boards out of position. The method shown at Fig. 226 is frequently used, the 7/8 or 1 inch plank being supported by 2 × 4 inch studs, which in turn are braced as shown. On cheap work the outside boarding is omitted, the earth being shaved with the shovel as near the position of outer casing as possible. Of course, this earth wall is only useful within a foot or so from the surface. At this point the outer boarding must commence, and be continued to top of foundation. In order to have the foundation level on top, it is best to level the wooden form all around the four sides. If the concrete is brought exactly to the top, and a straight edge is run along the edges of the form, the resulting wall must be level, provided the box has been made so. Concrete does not flow enough to level itself.

FRAMING

This is a subject on which volumes have been written. The general arrangement with the names and sizes of the various members is shown in the drawing, a design for a small cottage, or bungalow. (Fig. 227.)

The heavy timbers forming the sill are cut to the outside dimensions of foundation and halved at the corners. Fasten the joints with ten or twelve penny nails. Cut all corner posts exactly the same length, toenail at corners to sill, and hold in position by temporary braces. Plumb the posts as the braces are nailed. Two boys must work at this job, one holding the plumb and the other nailing the braces. Cut and halve the ends of plate the same length as sill, and nail to corner posts. Cut 2 × 4 studs same length as posts, then nail to sill and plate 16 inches apart on centres. The openings to be left for doors and windows will break up the even spacing of the studs, but it should be made as uniform as possible. The spaces for door and window frames are to be enclosed with double studs to give the necessary strength. Corner braces are very desirable and in the old-fashioned braced frame were mortised into plate and post, and sill and post. (Fig. 227_a_.)

For a simple structure the necessary bracing may be obtained by "letting into" the studding 3 × 1 inch strips, as shown in drawing. To do this hold the brace in the position it is to occupy, and make a pencil mark on both sides of it on each timber, sawing on the inside of these lines to a depth equal to thickness of brace. Remove the wood between saw cuts with a chisel. Test to see that brace comes flush with outside of studs, and nail securely in position.

When the frame is finished up to the roof the putting on of the siding may begin at any time.

SIDING

The outside of the building, siding or weather boarding, is an important item, as it is designed to protect the interior from sun, cold, and storms. It should be watertight, and may be made of various materials, put on in several ways.

In a house to be used in winter, the first layer should be of wide ship-lap boards. If put on diagonally it will act as a permanent bracing, and while this is the better way, it takes more time than horizontal siding. In either case nail to every stud and timber the board touches. Begin at the bottom of sill, break joints as the work progresses upward, and saw ends even with outside of posts.

At all door and window openings bring edges of siding flush with openings.

This inner siding is to be covered with building paper, door and window frames set, tin flashing nailed over doors and windows, and outer covering put on.

Before proceeding with outside sheathing, however, the roof should be framed and covered.

ROOFING

It is a difficult matter to say that one part of a house is more important than another, as all parts are important, but a building with an unstable or leaky roof is an abomination. The framing of the roof must be strong enough to withstand gales, blizzards, drenching rains, and the weight of tons of wet snow.

As the method of shingling has been described under tennis court shelter, it is only necessary to take up the subject of the frame. Boys will do well to confine their early efforts to plain sloping, or possibly hipped roofs.

These two styles are illustrated in Fig. 229.

The hip roof is the more pleasing and the more difficult to make. It reduces the attic space, if that is a consideration, and is harder to cover, or rather it consumes more time, as the question of whether a piece of work is difficult or not is really a question of whether or not you know how to do it.

The method of fitting the rafters is shown at Fig. 230. To find length of rafters, make a drawing to scale, in which _a-b_ is the height above plate level and _c-b_ half the width of the building measured on the plate or sill. The angle for cutting the mitre at the ridge may be obtained from the drawing, also the angles where the fit occurs at the plate. The length should be distance _a-c_ plus about two feet for the overhang.

A ridge board is usually inserted between the top ends of the rafters, and if made from a 7/8-inch board, half an inch should be deducted from the length of rafters to allow for the difference.

The shape of lower end of rafters will depend on the kind of finish or cornice to be used. Two kinds are shown, the first and simpler being suitable for a barn or rough building.

On account of the high price of lumber, most boys will be obliged to use the most inexpensive style of finish.

Cut all the rafters the same size, and in erecting space them as nearly two feet apart as possible.

The first pair should be flush with the edge of plate and temporarily held in position by braces of shingle lath. It will be necessary in erecting the roof to place timbers and floor boards across the top of plate as a temporary floor to work on. Nail rafters to ridge board, and plate with ten-penny wire nails. Two boys must work together on this job, as every part of the work must be plumb.

When all the rafters are in place, cut and fit the short studs between plate and rafters, being careful to leave the openings for windows in the places called for on the plan.

The ship-lap siding may now be continued up to top edge of rafters, and sawed off even with upper edge.

If novelty siding is used without any under sheathing, it may be treated in the same way.

Shingling may now be done as described under tennis court accessories.

WINDOW AND DOOR FRAMES

These may be bought at the mill ready made. Very few carpenters make their own, as they are staple articles coming in standard sizes. Second-hand sashes and frames may often be bought at very reasonable rates, and it never pays to make either.

Set the frames in the openings left for them, and nail to studs. To make sure that the fit between frames and openings shall be right, it is best to take the plans to the mill, and explain to the mill man just what is desired.

FLOORING

The floor beams may be set at any time after the frame has been erected up to the plate. As it will be necessary to work around inside more or less, the sooner they are in position the better. As these beams, supposed to be 10 × 2 inches, often vary in width, the floor is liable to be uneven, unless they are cut to fit the sill.

The amount cut out need not be very much, but a certain distance, say nine inches, should be marked from the top edge, and the lower corner cut out as shown at _d_ (Fig. 230). This will bring all the top edges level, when they are in position.

The span of the floor beams--the distance from the sill to the next support--is important, as a floor is called upon sometimes to support great weight, as when a number of people are present, or a heavy piece of furniture such as a piano rests on it.

For floor beams 2 × 8, a span of not over twelve feet should be allowed; for 2 × 10 a slightly greater span may be used; but in either case the supporting beam in the centre of the floor should be halved into the sill with upper edge flush, and should be supported at intervals of ten feet by posts set in the floor of cellar, or to a depth of three feet in the ground in case there is no cellar. This supporting beam should be placed when the sill is set on foundation. Nail floor beams to sill, and where the two beams from opposite sides of the building lap or pass each other over the beam in centre, nail them to each other and to the beam.

The flooring of tongue and groove stuff may now be laid, cutting ends square and fitting them up close to studding, or, what is still better, clear out to the sheathing.

The outside weather boards may now be put on, after deciding on one of the corner finishes described under poultry house. A flashing of tin--painted--must be placed over door and window frames, before the clapboarding or siding reaches these points. This siding is sawed off square, and makes a butt joint with the outer casing of door and window frames.

Some form of building paper is nailed to the first siding in good buildings, and pays for itself in the long run, by reducing the amount of fuel necessary to heat the building in winter.

If the house is a sea-shore cottage or camp only to be used in summer, both the paper and inner sheathing may be omitted, and the expense account materially reduced.

The finishing of the interior may be left to the last, or done on stormy days. In the meanwhile, several important questions must be settled. One is the style of flue or chimney to be provided for the stove.

If the building is to be permanent, a brick chimney should be built by a mason. The danger of fire originating from defective bricklaying makes it advisable to have this work done by a tradesman.

For summer cottages or camp buildings a simple stove pipe can be used, but in any event it should be put up before the final roof covering is on, and "flashed," that is protected by tin laid over the roof timbers, and made watertight. This does away with leaks around the chimney, and the tin should be put on in such a way as to prevent the shingles from coming in direct contact with the hot chimney.

In these days of oil stoves, which are often used for summer cooking, the chimney may be omitted entirely. At the same time it must be remembered that there are cold, damp nights, when a stove is very comfortable at the shore or in the woods.

In regard to interior finish, if the walls are to be plastered, three coats will need to be put on by a skilled plasterer. Thin yellow pine ceiling stuff, often used for camp buildings, is easily put on, and quite satisfactory. Laid on diagonally it is very pleasing, but the beads catch more dust than the vertical strips do. The latter method calls for horizontal strips laid between the studs for nailing, while a simple quarter round moulding laid in all corners gives the finish. A common practice in camps is to have no interior wall covering, but to leave the timbers exposed. For a dwelling, the frame should be of dressed lumber, which may be stained to conform with the general colour scheme.

The inside trim around doors and windows may now be put on. Three methods of finishing around windows are shown at _e_, _f_, _g_ (Fig. 230), and one of these types should be adopted before ordering the trim from the mill. This work should be simplified as much as possible, not only to save time, but because decoration may well be left to pictures, artistic metal work, trophies, and things which are of interest from their history or association.

DOORS AND WINDOWS

If second-hand material is not used it is advisable to purchase these staple articles from a mill where they are made in standard sizes.

When ordered for certain size spaces they come a little too large. This allowance is for material to be removed in fitting. Inside doors are usually the last things to be hung. The windows should be hung as soon as the construction will allow it, in order to keep out rain.

Secure the pulleys for upper and lower sash into the window frame on both sides of parting strip about four inches from top of window frame.

Attach the sash cord and find its proper length by experiment. Tie securely to sash weights. See that the two sashes make a good, tight joint where they meet, and tack the window stop to frame with brads. The stop is to be ordered with the trim, and mitred at the top. The construction at the sill is shown at _a_ (Fig. 230).

The arrangement of door frames is shown at _b_. After mitring the door stop, nail to door frame at a distance from its edge equal to thickness of door. Fit the door by planing to the space inside frame. The hinges are put on as shown, being sunk flush with edge of both door and door frame. When hanging the door, it is a good plan to place small wedges under it, to allow for the sag which will result as soon as its weight is thrown on the hinges.

Saddles are usually placed under doors to allow them to swing clear of carpet and rugs. To allow for the thickness of these saddles, 3/4 inch should be allowed between floor and bottom of door. The saddles are to be fitted around edges of door frame, making a neat finish.

For plastered walls a six-inch base board is necessary. This may be put on with butt joints and nailed to studding with small head finishing nails, as for all trim.

The base is usually topped by a base moulding mitred in the corners.

This style of construction is for a permanent house. For rough or temporary buildings, many modifications may be adopted. Batten doors, as described for the poultry house, may be cheaply and readily made.

Batten blinds made by the same method are very desirable for buildings like summer camps, which are to be vacant for long periods. This does away with the temptation some people find to break windows in unoccupied houses.

The siding for a small building may be of tongue and groove boards put on vertically, and now that lumber is so expensive these items are all important.

The lumber from packing cases may be used for making very many of the pieces of furniture in a camp, such as stools, benches, tables, shelves, cupboards, bookcases, etc. Many of these useful articles can be made without tearing the boxes apart.

A very useful chest and seat combined may be made by fitting a box with a strong cover, strengthened by cleats on its under side and hinged with strap hinges to the back.

A cushion of burlap filled with shavings, straw, seaweed, or sweet grass will make this a very satisfactory settee, and the storage space inside will always be available. The outside of the box should be smoothed, all nail holes filled with putty, and the whole thing stained.

Very interesting panelling effects may be obtained by tacking on strips of the same thickness as the outside cleats.

Where the supply of wood is limited, many similar articles will suggest themselves to the young carpenter. The chair shown at Fig. 231_a_ can all be made of wood from packing boxes, except the square legs. These may be obtained by sawing 2 × 4 inch spruce in half and planing smooth. The rails can be put on with mortise and tenon, or they may be gained into the legs and fastened with nails or screws. The seat is built up of several pieces fastened to cleats on under side, with front edges rounded. To make this hard bottomed chair more comfortable, have a thin cushion of canvas or burlap fastened by a canvas cover and tacked to edges. The wide strip across the back may be treated in the same way. One coat of stain, or two of Japalac or some similarly prepared varnish will make a very serviceable finish for camp purposes.

The proportions of a porch settee of the same general character are given at Fig. 231_b_. The legs may be cut out of pieces of spruce studding, and all but the long rails obtained from box material. These long pieces may be cut from 7/8-inch siding left over when putting up the cabin. Floor boards with tongue and groove planed off will answer very well.

The long back strip will be more rigid if mortised into the ends, and the upright strips will be needed to give it the necessary strength.

One of the most comfortable articles for a camp in the woods is the couch hammock. The materials required are:

A cot.
Four yards of strong canvas a yard wide.
Forty feet of clothesline.
Two chains or strong pieces of rope about 4 or 5 feet long.
A grommet set and some grommets.

Remove the legs from the cot. They are usually attached by bolts or rivets. If the latter, cut with a cold chisel.

Lay the canvas in one piece on the floor and place the cot at its centre. Make pencil marks at the ends to indicate where the fold begins as at B B (Fig. 232). Lap the canvas as shown and sew securely, leaving a space at the fold for the clothesline to pass through.

The square ends are to be hemmed and folded over pieces of broomstick.

With the grommet punch make holes through the canvas just below the broomstick and secure with the grommets. Make these holes about 5 inches apart. They are to hold the line which is to pass from iron fitting C through first grommet hole and back until it has passed once through each grommet.

The fitting is found on all hammocks and can be taken from an old one, or an iron ring may be substituted. Before beginning to weave the rope through the grommets, pass its end down to B and make fast to a stout screw eye fastened to under side of frame of cot. This brings the weight on the rope instead of on the canvas, an important item when five or six people sit on the couch at one time. Treat both ends alike. The canvas will be wide enough to fold up and entirely cover the edges of cot. When everything has been adjusted, fasten the chains or heavy rope to the iron rings, and secure to the trees or veranda columns by heavy hooks. A light mattress covered with blankets, or a specially made cushion to cover the whole cot, and several sofa pillows will add the finishing touches to a very serviceable and satisfactory article.

The cost will be about one third of those on sale, and this may be reduced 50 per cent. if a grommet set can be borrowed, as this is the chief item of expense, assuming that an old cot is used.

This hammock should not be left out in the rain, as its steel springs will rust.

XLIX

STAINING, POLISHING, AND FINISHING

This branch of woodwork is a trade by itself and under modern methods of specialization the men who do this work do nothing else. The methods of finishing are legion and every polisher has a few little "kinks" of his own which he regards as trade secrets.

The personal equation enters very largely into the work, and if twenty boys have a given method explained to them and they all polish, say, a box of the same size and material, there will result twenty different kinds of polished surfaces.

This is due to difference in temperament. Some boys are patient and painstaking. Others are nervously anxious to get through and see how it looks. It is a fact particularly true of finishing that it cannot be hurried without endangering the result. Every coat must be thoroughly dry and hard before the next one is put on. Different woods require different treatment, and the elements of good taste, colour, and harmony all enter into the problem.

These statements are not made to discourage the young woodworker, because finishing can be done well by any boy who will use reasonable care, but to emphasize the fact that it is poor policy to make a fine piece of woodwork and then spoil it at the last moment by hurry.

Staining is something on which opinions differ greatly. Some artists claim that only the natural colour of the wood should be used, but a great deal of staining is done, and we must leave artistic arguments to others.

The extent to which staining is carried may be illustrated by the following finishes used on one kind of wood--oak:

Golden oak Antwerp oak Rotterdam
English oak Ox blood Antique
Forest green Weathered oak Cathedral oak
Austrian Flemish brown Flemish green
Silver gray Sumatra brown Filipino
Mission oak Malachite Fumed oak
Bog oak

The writer believes that staining to make imitations is wrong, such as staining cherry or birch to give the impression of mahogany.

The list of materials for staining is very bewildering, and it is advisable to reduce the list to a few reliable ones and learn to use them well. They may be divided roughly into three classes: oil stains, water stains, and stains produced from drugs or chemicals.

Oil stains are dry colours ground in oil such as chrome yellow, Prussian blue, burnt umber, burnt sienna, etc. When preparing one of these for use, thin with turpentine and linseed oil and apply with a brush. After it has stood for a few moments rub off with a piece of cotton waste or rag.

Water stains are colours dissolved in water.

After applying this kind allow it to dry. Sand-paper the surface flat and apply a second coat of half the strength.

Stains produced from drugs and chemicals include such materials as logwood, bichromate of potash, ammonia, iron sulphate, acetate of iron, etc.

The preparation of the surfaces to be finished is very important and means the removing of any defects, such as scratches, by means of plane, scraper, and fine sand-paper.

These defects always show much more prominently after polishing than before, so that too great pains cannot be taken in preparation. Assuming that the surface is ready, the first question to be considered is whether the wood is open or close grained. If an open grained wood, a coat of filler may be used; if close grained this may be dispensed with. The following list will enable the beginner to decide:

Open grained woods requiring filler: Oak, ash, chestnut, mahogany,
walnut, butternut. Close grained woods; no filler required: White
wood, pine, cherry, birch, beech, gum, sycamore or buttonball;
maple, cedar, cypress, red wood.

Filler may be made at home, but it is a staple article to be found in paint stores and it is advisable to buy it ready made. It comes in paste and liquid forms, and the paste is recommended. It must be thinned with turpentine to the consistency of cream and applied with a brush. As soon as it begins to dry, rub off the excess across the grain with a handful of excelsior, waste, burlap, or rags and allow it to stand over night to dry.

When the wood is to be stained the colour is frequently mixed with the filler.

The object of all this is to fill up the pores of the wood to give a flat, solid surface for the polishing. Sometimes even on open grained woods filler is omitted entirely.

Suppose that the work in hand is a footstool or tabourette made of oak and we wish to give it a forest green finish.

The process would be as follows:

Prepare the stain by mixing a small quantity of chrome yellow and Prussian blue on a piece of wood. Mix thoroughly with a putty knife or old chisel and thin with boiled linseed oil and turpentine; add blue or yellow until a beautiful dark green is obtained. Add this to the filler, using turpentine for thinning, until the whole mass of liquid is the desired colour and as thick as cream. Paint the footstool all over with this filler. As soon as it starts to dry, rub off as explained.

The next day sand-paper smooth and give a coat of shellac. When hard, sand-paper flat and give a second coat of shellac.

From this point on the process depends on whether a glossy polish is desired or a dead flat surface. For an article of furniture like a footstool a highly polished surface would be a mistake, as it would soon be scratched, and while furniture is not to be abused, it is to be used, and shoe nails make scratches.

A dead flat surface may be obtained by rubbing down the third coat of shellac with fine ground pumice stone or rotten stone and water. If too flat, rub the surface with raw linseed oil and wipe dry.

Some boys will obtain a better finish with two coats of shellac than others will with four.

After the first coat of shellac, varnish is often used for the remaining coats, but it takes much longer to harden and requires careful handling.

Shellac is a product obtained from certain trees in the Orient. It may be bought in the dry state at paint stores and dissolved in alcohol. Grain alcohol is the best and most expensive, but wood alcohol is cheaper and will answer all ordinary purposes. The shellac may be bought in cans all ready for use, and there are two distinct kinds--orange and white.

White shellac is the more expensive, but should be used on light-coloured woods, such as maple, to avoid spoiling the colour.

Varnish comes in so many grades and kinds that it is best to go to a reliable dealer and tell him just for what purpose you expect to use it. There are outside varnishes, rubbing varnishes, light flowing varnishes, etc.

When by exposure it becomes thick so that the brush drags, it should be thinned with a little turpentine.

There is a great difference in the methods of using shellac and varnish. The former being dissolved in alcohol evaporates quickly, so that it must be put on thinly and as rapidly as possible. Varnish, on the other hand, may take forty-eight hours or more to dry, so that the brush can be drawn over the surface several times to remove air bubbles. It is not possible to do this with shellac. The brush used in shellac should never be laid on the top of the jar or can, as it will harden in a very short time. The care of brushes is an important item. Varnish brushes should be cleaned with turpentine, shellac brushes with alcohol, and when cleaned it is better to keep all brushes in a pail of water than to allow them to become dry.

The jar or wide mouthed bottle used for shellac should be kept covered else a great deal will be lost by evaporation. A jam jar makes a convenient receptacle for this, as it has an opening wide enough to allow the use of a flat brush. Evaporation may be prevented by inverting another jar of the same size over it. The shellac on the rim will hold them together practically airtight with the brush inside.

RELATIVE ADVANTAGES OF OIL AND WATER STAINS

The merits of these two classes of stains may be stated briefly. Water stains enter more deeply into the pores of the wood because of their lighter body. The hard parts of the surface hold practically none of the stain and constitute the high lights of the finished surface. But water stains raise the grain and make sand-papering necessary to bring the surface flat again. For this reason, some polishers first give a coat of water to raise the grain and when dry sand-paper flat before staining.

Oil stains do not raise the grain, but owing to their heavier body do not penetrate so deeply and more of the stain is lost in rubbing off. Oil has a tendency to darken wood, so that wood stained with oil colours has a tendency to become clouded or muddy with age.

For staining old work, oil stains should be used rather than water stains. Old work has the pores already filled and water has little chance to penetrate.

Some chemicals and aniline dyes are very satisfactory. Bismarck brown, which may be bought at the chemist's as a powder, is soluble in alcohol and gives a rich reddish brown. It is very powerful and a very small quantity is necessary. Bichromate of potash comes in the form of lumps and crystals. It is soluble in water. Put half a dozen crystals in a quart milk bottle of water and allow it to stand over night. Warm or hot water will dissolve the crystals more quickly. It is to be put on with a brush and gives rich brown tints, the shade depending on its strength, the kind of wood and the number of coats. It gives excellent results on oak and chestnut, and is used to "age" bay wood to a dark mahogany, while several coats of it will bring white wood to the colour of natural black walnut.

Each coat must be allowed to dry and then be rubbed flat with fine sand-paper.

This treatment may be followed by two or three coats of orange shellac, rubbed down.

For "antique" finish on oak or chestnut, dissolve lampblack in turpentine, mix with filler and proceed with polishing as explained.

A decoction of logwood is often used to produce dark and even black effects. The logwood extract is cheap and comes in the form of gum or resin. Several lumps of this are boiled in a gallon of water and applied as any water stain.

Acetate of iron, made from iron filings and vinegar, is used for dark browns occasionally. The filings should be allowed to stand for several days in the vinegar. The acid present is acetic. It unites with the iron forming the acetate of iron.

POLISHING

The method given above is for a substantial solid finish, but sometimes a boy will have some difficulty in obtaining the desired finish through lack of patience or some other cause.

A French polish may help to give the finishing touch. For this a piece of cheese cloth about 6 inches square, a piece of cotton waste about the size of a walnut, a little shellac and raw linseed oil are necessary.

Dip the waste lightly in shellac; fold the cheese cloth around it, making a soft pad, dip the pad in the oil and rub quickly and constantly in circles, gradually covering the whole surface. As the shellac hardens or sticks, use a little more oil and squeeze the pad slightly to bring the shellac through the cheese cloth. The oil prevents the shellac from sticking and a little experience will give the right balance between the two. When the polish becomes so bright that it shows the slightest finger mark, wipe dry with a piece of soft flannel.

WAX POLISH

This is used where a dull or flat finish is required. It can be applied directly after staining or filling.

Dissolve beeswax in turpentine to the consistency of filler. Heat hastens this part of the process, but is not necessary unless time is a consideration. The wax is applied with a soft rag or waste and rubbed and rubbed. The turpentine evaporates, leaving the wax. Several rubbings at intervals of a week will give the desired effect, and the surface may be brightened at any time by an additional application.

It should be remembered in all forms of polishing that dust is the great enemy. Wherever possible a piece of furniture after receiving a coat of shellac or varnish should be placed in a room or closet where no dust can settle on it. It should also be kept out of the sun to avoid blistering. The action of some stains like bichromate of potash is affected by the sun and should be either kept out of direct sunlight entirely or so placed that all parts receive the same amount, else the parts in shadow will be of a different shade from the rest of the surface.

L

DURABILITY, DECAY, AND PRESERVATION OF WOOD

It is now known that decay in wood is caused by fungi or low forms of plant life which cannot live without a certain amount of water, food, heat and air.

A fence post decays first at the place where it enters the ground, because at that point the conditions are most favourable. If wood can be kept entirely under water, one item--air--is lacking, so the fungous growths cannot exist and the wood will last indefinitely. This has been proved in many instances. One of the old Viking ships was raised from the bottom of the Christiania Fjord, Norway, after having been under water for a thousand years and it was found to be in a perfect state of preservation. Even the rudder oar or steerboard and wooden shields were intact.

As soon as it was brought into the air the process of decay began, and it became necessary to coat it with preservative. It stands to-day, 103 feet long, in the museum at Christiania.

Many other instances of under-water preservation might be mentioned.

The other extreme is also true. Wood which is kept perfectly dry will last indefinitely, as in the case of woodwork taken from the pyramids of Egypt, 3,000 years old, which is found to be perfectly preserved.

But when wood is alternately wet and dry it decays rapidly. A pile driven into the bottom of a tidal river is a good illustration. If such a pile be divided into four sections (see Fig. 233), _a_ is always in the ground, _b_ is always in the water, _c_ is alternately in air and water, _d_ is always in the air. Sections _a_ and _b_ may be considered to be under the same conditions and should last the longest; _c_ should decay first: _d_ would last indefinitely if the atmosphere were always perfectly dry; but humidity and rain, air and heat combined finally bring about decay, and although this part of the pile will last longer than _c_ it will in time decay. Section _c_ should be coated with a preservative.

Various woods under the same conditions act very differently and according to no well understood law. For example, in contact with the soil black locust is our most durable wood. It is very hard, and its life under these conditions is estimated at from ninety to a hundred years. Red cedar comes next, though it is soft wood. Oak decays in a few years; chestnut, much softer, lasts two or three times as long. Our approaching timber famine has induced a study of this subject, since the preservation of wood is becoming an absolute necessity.

It has been found that certain materials put on the wood before it is placed in the ground prolong its life. Coal tar, wood tar, paint, and creosote all help, but creosote has so far proved to be the best. It is one of the by-products of coal tar and is being used extensively by the railroad companies for prolonging the life of ties.

Experiments with creosote have brought out some very interesting facts. It has been found that after being treated with the hot creosote all woods resist decay alike, regardless of their hardness or softness. Consequently, a treated cheap wood will last as long as an originally valuable one. This is a great gain, as it allows us to make use of wood like the poplar which would otherwise be practically of no value.

The various coatings we put on wood, such as paint, varnish, oil, etc., are intended not only to beautify but to preserve it, which they do by filling up the pores and excluding moisture, preventing fungous growths, etc. All of these coatings should be put only on dry wood, else they prevent evaporation of the sap and may hasten decay.

Drying lumber increases its strength, as it has been found by experiment, even as much as 400 per cent. if no checking occurs. When this happens it counteracts much of the gain, and if the wood absorbs moisture once more the strength will decrease. The strength of the various timbers varies greatly, and sap wood is usually weaker than heart wood.

The strains that may be brought to bear on timbers are illustrated in Fig. 234, the arrows indicating the directions in which the forces operate. At _a_ the wood is under tension, the forces at work on it tending to pull it apart. At _b_ the piece is under compression, the forces tending to reduce its length by forcing its fibres together. A pillar supporting a weight is under compression. At _c_ the weight tends to bend the beam. The upper part is under tension, the lower part under compression. This is known as beam action, and depends on whether the beam is supported at one end, as shown, or on both ends. Also it is important to know whether the beam has a uniformly distributed load or whether the weight is at one point only. The problems relative to beam action are largely of an engineering character and involve considerable mathematics.

Shearing is the sliding of one part of the timber along the grain. If a piece of wood is cut to the form shown at _d_ and a weight applied at _e_, the tendency will be for this upper part to slide down as shown at _f_. When this occurs, shearing has taken place.

The strength of wood differs in resisting these various strains, the tensile strength being greater than the crushing or compressive strength. Ash, for example, has a tensile strength of 16,000 pounds to the square inch, but its crushing strength is only 6800 for the same size. The tensile strength of dry white pine is 10,000 pounds, its crushing strength 5400 pounds, and its shearing strength varies from 250 pounds to 500 pounds, showing that its weakest point is along the grain. If the young woodworker becomes ambitious enough to think of designing a bridge or large building he can find these figures in any engineers' hand-book. There are so many important factors to be considered that the amateur will do well to go ahead with great caution. Knots and other defects reduce the proportionate strength of large beams greatly, so that it would not be safe to assume that a beam 6 inches square would be 36 times as strong as a piece 1 inch square.

In upright posts of considerable length, not alone the crushing strength must be considered, but a bending action enters into the problem. Wherever the question of danger to life enters, as in a bridge or a house, it is wise to leave a large margin for safety. We realize this fully when we read of a grand stand holding hundreds or thousands of people collapsing under the weight. The architect has also to reckon with still other elements, such as wind pressure and vibration.

LI

MATHEMATICS OF WOODWORK

The woodworker soon discovers that arithmetic is a very practical and necessary subject. He will meet many problems both in drawing and in actual construction which test his ability and call for some knowledge even of elementary geometry. It is important to be able to estimate from his drawing just how much lumber will be needed. He will soon discover through intercourse with dealers in lumber that there are certain standard sizes, and he should make his designs as far as possible conform at least to standard thicknesses.

Common boards are sawed 1 inch thick. When dressed on two sides the thickness is reduced to 7/8. In planning some part of a structure to be 1 inch thick it is better to make the dimension 7/8 inch, else it will be necessary to have heavier material planed to 1 inch and the cost will be that of the heavier lumber, plus the expense of planing. In buying 1/2-inch dressed lumber, very often inch boards are dressed down to the required thickness, and the purchaser pays for 1-inch wood, in addition to the dressing. The boy is surprised to find that it costs more for 1/2-inch than for inch material. Standard lengths are 10, 12, 14, 16, etc., feet. Widths vary, and as wood shrinks only across the grain--with one or two exceptions--this dimension cannot be depended on, as the amount of shrinkage depends somewhat on the age after cutting. Whenever possible, it is wise to go to the lumber yard and select your own material, choosing boards that are free from knots, shakes, etc. Clear lumber--free from knots--costs more, but is worth the difference.

MEASUREMENTS

A measurement is a comparison. We measure the length of a lot by comparing it with the standard of length, the yard or foot. We measure a farm by comparing its area with the standard unit of surface measure, the acre, square rod, or square yard.

In every measurement we must first have an accepted standard unit. The history of units of measurement is a very interesting one, and its difficulty arises from the fact that no two things in nature are the same. One of the ancient units of length was the cubit, supposed to be the length of a man's forearm, from the elbow to the end of the middle finger. This, like other natural units, varied and was therefore unreliable. As civilization progressed it became necessary for the various governments to take up the question of units of measurements and to define just what they should be.

Our own standards are copied from those of Great Britain, and although congress is empowered to prescribe what shall be our units, little has been changed, so that with few exceptions we are still using English measurements.

The almost hopeless confusion and unnecessary complication of figures is shown in the following tables as compared with the metric system:

12 inches = 1 foot .001 = millimetre
3 feet = 1 yard
(standard) .01 = centimetre

5-1/2 yards } .1 = decimetre
or } = 1 rod
16-1/2 feet } 1. = metre

320 rods } 10. = dekametre
or }
1760 yards } = 1 mile 100. = hectometre
or }
5280 feet } 1000. = kilometre

The original English definition of an inch was "three barley corns" with rounded ends. The meter is 1/10,000,000 (one ten-millionth) of a quadrant of the earth's circumference, _i. e._, the distance from the pole to the equator measured along one of the meridians of longitude. The length of three barley corns might be different from the next three, so here was the original difficulty again. The designers of the metric system went back to the earth itself as the only unchangeable thing--and--are we sure there is no change in the earth's circumference? The great advantage of the metric is that it is a decimal system and includes weights as well as surfaces and solids. Our weights are even more distracting than our long measure. We have in fact two kinds of weight measure--troy and avoirdupois.

TROY AVOIRDUPOIS METRIC

24 gr. = 1 pwt. 16 oz. = 1 lb. .001 milligram
20 pwt. = 1 oz. 112 lb. = 1 cwt. .01 centigram
12 oz. = 1 lb. 20 cwt. = 1 ton .1 decigram
5760 gr. = 1 lb. 2240 lb. = 1 long ton 1. gram
2000 lb. = 1 short ton 10. dekigram
100 lb. = 1 short cwt. 100. hectogram
7000 gr. = 1 lb. 1000. kilogram

In surface measurements, the same differences are seen:

AMERICAN OR ENGLISH METRIC

9 sq. ft. = 1 sq. yd. .0001 sq. centimetre
30-1/4 sq. yds. = 1 sq. rod .01 sq. decimetre
160 sq. rods } 1. sq. metre
4840 sq. yds. } = 1 acre 100. are
640 acres = 1 sq. mile 10,000. hectare
1,000,000. sq. kilometre

In measures of volumes we are as badly off:

DRY LIQUID METRIC

2 pints = 1 quart 2 pints = 1 quart .001 millilitre
8 quarts = 1 peck 4 qts. = 1 gallon .01 centilitre
4 pecks = 1 bushel 1 gal. = 231 cu. ins. .1 decilitre
4 quarts = 268.8 cu. ins. 1. litre or cu. decim.
1 heaped bushel = 1-1/4 10. dekalitre
struck bushels. 100. hectolitre
The cone in a heaped 1000. cu. metre or
bushel must be not kilolitre
less than 6 ins. high.

As if this were not enough, when we go to sea we use another system. The depth of water is measured in fathoms (6 feet = 1 fathom), the mile is 6086.07 feet long = 1.152664 land miles, and 3 sea miles = 1 league. In our cubic measure:

1728 cubic inches = 1 cubic foot
27 cubic feet = 1 cubic yard
A cord of wood is 4 ft. × 4 ft. × 8 ft. = 128 cubic feet.
A perch of masonry is 16-1/2 × 1-1/2 × 1 = 24.75 cubic feet

Isn't it about time we used the metric system? The reader will not mind one more standard unit. Lumber is measured by the board foot. Its dimensions are 12 × 12 × 1 inches; it contains 144 cubic inches and is 1/12 of a cubic foot. A board 10 feet long, 1 foot wide and 1 inch thick contains 10 board feet. One of the same length and width but only 1/2 inch thick contains 5 board feet.

The contents of any piece of timber reduced to cubic inches can be found in board feet by dividing by 144, or from cubic feet by multiplying by 12. As simple examples: How many board feet in a piece of lumber containing 2,880 cubic inches? 2880/144 = 20 board feet. How much wood in a joist 16 feet long, 12 inches wide and 6 inches thick? 16 × 1 × 1/2 = 8 cubic feet: 8 × 12 = 96 board feet. A simpler method may be used in most cases. How much wood in a beam 9 inches x 6 inches, 14 feet long? Imagine this timber built up of 1-inch boards. As there are nine of them, and each 14 ft. × 1/2 foot × 1 inch and contains 7 board feet (Fig. 235), 7 × 9 = 63 board feet. Again, how much wood in a timber 8 inches × 4 inches, 18 feet long? This is equivalent to 4 boards 1 inch thick and 8 inches or 2/3 foot wide. Each board is 18 × 2/3 × 1 = 12 board feet, and 12 × 4 = 48, answer. (See _b_, Fig. 235).

To take a theoretical case: How much wood in a solid circular log of uniform diameter, 16 inches in diameter, 13 feet and 9 inches long? Find the area of a 16-inch circle in square inches, multiply by length in inches and divide by 144.

16 × 16 × .7854 = 201 13 ft. 9 in. = 165 inches

(201 × 165)/144 = 130 - 45/144 board feet

It is not likely that a boy would often need to figure such an example, but if the approximate weight of such a timber were desired, this method could be used, reducing the answer to cubic feet and multiplying by the weight per cubic foot.

A knowledge of square root is often of great value to the woodworker for estimating diagonals or squaring foundations. The latter is usually based on the known relation of an hypothenuse to its base and altitude. It is the carpenters' 3-4-5 rule. The square of the base added to the square of the altitude = square of the hypothenuse. 3² = 9, 4² = 16; 9 + 16 = 25. The square root of 25 is 5. (See Fig. 235). To square the corner of his foundation the carpenter measures 6 feet one way and 8 the other. If his 10-foot pole just touches the two marks, the corner is square. 6² = 36, 8² = 64; 36 + 64 = 100. [sqrt]100 = 10. This method was used in laying out the tennis court, the figures being 36, 48, 60--3, 4, and 5 multiplied by 12.