CARPENTRY FOR BOYS IN A SIMPLE LANGUAGE, INCLUDING CHAPTERS ON DRAWING, LAYING OUT WORK, DESIGNING AND ARCHITECTURE WITH 250 ORIGINAL ILLUSTRATIONS TEXT

compared with many others, looks like an intricate maze of beams, struts and braces, but it is, nevertheless, so harmonized that the effect is most pleasing to the eye, and its very appearance gives the impression of grandeur and strength. Nearly all of the forms shown herein have come down to us from mediæval times, when more stress was laid on wooden structures than at the present time, but most of the stone and metal buildings grew out of the wooden prototypes. Now the prime object of nearly all the double-roofed trusses was to utilize the space between the rafters so as to give height and majesty to the interior. A large dome is grand, owing to its great simplicity, but the same plain outlines, or lack of ornamentation, in the ceiling of a square or rectangular building would be painful to view, hence, the braces, beams, plates, and various supports of the roofed truss served as ornamental parts, and it is in this particular that the art of the designer finds his inspiration. Before proceeding to apply the matter of ornamentation, it might be well to develop these roof forms, starting with the old type Barn Roof, where the space between the rafters must be utilized for the storage of hay. [Illustration: _Fig. 284. Gambrel Roof._] _The Gambrel Roof_, Fig. 284, requires a tie beam, (A), as shown, but the space above the beam is free of all obstructions, and gives a large storage space. The roof has two sets of rafters (B, C), and of different pitch, the lower rafters (B) having a pitch of about 30 degrees, and the upper ones (C), about 45 degrees. A tie bar (D) joins the middle portion of each of the rafters (B, C) and another tie bar (E) joins the middle part of the rafter (B), and the supporting post (F). The cross tie beam (G) completes the span, and a little study will show the complete interdependence of one piece upon the other. [Illustration: _Fig. 285. Purlin Roof._] _The Purlin Roof_ is a type of structure used very largely throughout the United States, for wide barns. (A) is the cross beam; (B, B) the purlin posts; (C, C) the purlin plates; (D, D) the rafters; and (E, E) the supporting braces. The rafters (D) are in two sections, the distance from the eaves to the comb being too great for single length rafters, and the purlin plates are not designed to make what is called a "self-supporting" roof, but merely to serve as supports for the regular rafters. _The Princess Truss_, on the other hand, is designed to act as a support for the different lengths of rafters (A, B, C), and as a means for holding the roof. It is adapted for low pitch and wide spans. [Illustration: _Fig. 286. Princess Truss._] The main truss is made up of the cross beam (D), rafters (E, E) and thrust beam (F). Purlin posts (G, G) are placed at an angle intermediate the ends of the rafters, and the purlin plates (H, H) support the roof rafters (A, B, C); I, I are the vertical tie rods. This type is probably the oldest form of truss for building purposes, and it has been modified in many ways, the most usual modification being the substitution of posts for the tie rods (I, I). Following out the foregoing forms, we may call attention to one more type which permitted ornamentation to a considerable degree, although it still required the tie beam. In fact the tie beam itself was the feature on which the architect depended to make the greatest effect by elaborating it. This is shown in Fig. 287, and is called the _Arched_, or _Cambered, Tie Beam Truss_. It is a very old type, samples of which have been found which take it back to a very remote age. [Illustration: _Fig. 287. Arched, or Cambered, Tie Beam._] The tie beam A, in wide spans, was made in two sections, properly tied together, and sometimes the outer ends were very wide, and to add to the effect of the arch, it might also be raised in the middle, something in the form shown by the dotted line (B). _The Mansard_ is what may be called a double-mounted roof, and it will be seen how it was evolved from the preceding types. It will be noted that the simple truss formed by the members (A, B, C) is merely superposed on the leaning posts, the tie beam also being necessary in this construction. [Illustration: _Fig. 288. The Mansard._] But the most elaborate formations are those which were intended to provide trusses for buildings wherein the tie beams were dispensed with. The simplest form known is called the _Scissors Beam_, illustrated in Fig. 289. This has been utilized for small spaces, and steep pitches. Each rafter (A) has an angled beam or brace (B), springing from its base, to the opposite rafter (A), to which it is joined, midway between its ends, as at C. Where the two braces (B) cross each other they are secured together, as at D. As a result, three trusses are formed, namely, 1, 2, 3, and it possesses remarkable strength. [Illustration: _Fig. 289. Scissors Beam._] BRACED COLLAR BEAM.--This is a modification of the last type, but is adapted for thick walls only. The tie rod braces (A, A) have to be brought down low to give a good bracing action, and this arrangement is capable of considerable ornamentation. The steeper the pitch the higher up would be the inner and lower brace posts (B, B) which were supported by the top of the wall. This form is not available for wide spans, and is shown to illustrate how the development was made into the succeeding types. [Illustration: _Fig. 290. Braced Collar Beam._] THE RIB AND COLLAR TRUSS, Fig. 291, is the first important structural arrangement which permitted the architect to give full sway to embellishment. The inwardly-projecting members (A, A) are called _Hammer Beams_. They were devised as a substitute for the thick walls used in the Braced Collar Beam Truss, and small brackets (B, B) were placed beneath as supports. [Illustration: _Fig. 291. Rib and Collar Truss._] The short tie beam (C), near the apex, serves as the member to receive the thrust and stress of the curved ribs (D, D). It forms a most graceful type of roof, and is capable of the most exquisite ornamentation, but it is used for the high pitched roofs only. [Illustration: _Fig. 290-1/2. Hammer Beam Truss._] The acme of all constructions, in which strength, beauty, and capacity for ornamentation are blended, is the _Hammer Beam Truss_. Here the hammer beam projects inwardly farther than in the preceding figure, and has a deeper bracket (B), and this also extends down the pendant post (C) a greater distance. The curved supporting arch (D), on each side, is not ribbed, as in the Rib and Collar Truss, but instead, is provided with openwork (not shown herein), together with beadings and moldings, and other ornamental characteristics, and some of the most beautiful architectural forms in existence are in this type of roof. What are called Flying Buttresses (E) are sometimes used in connection with the Hammer Beam Truss, which, with heavy roofs and wide spans, is found to be absolutely necessary. CHAPTER XX ON THE CONSTRUCTION OF JOINTS In uniting two or more elements, some particular type of joint is necessary. In framing timbers, in making braces, in roof construction and supports, in floor beams, and in numerous other places, where strength is required, the workman should have at his command a knowledge of the most serviceable methods. Illustrations can most forcibly convey the different types; but the sizes must be determined by the character of the material you are working with. Our aim is to give the idea involved, and the name by which each is known. [Illustration: _Fig. 292. Bridle Joints._] Reference has been made in Chapter X, to certain forms of scarfing and lapping pieces. This chapter has to do with a variety of other structural forms, but principally with such as are used in heavy building work, and in cases where neither fish plates nor scarfing will answer the purpose. [Illustration: _Fig. 293. Spur Tenon._] [Illustration: _Fig. 294. Saddle Joints._] BRIDLE JOINTS.--This is a form of joint where permanency is not desired, and where it is necessary to readily seat or unseat the vertical timber. It is also obvious that the socket for the upright is of such a character that it will not weaken it to any great extent. SPUR TENON.--This tenon can be used in many places where the regular one is not available. This, like the preceding, is used where the parts are desired to be detachable, and the second form is one which is used in many structures. SADDLE JOINT.--This is still another manner in which a quickly detachable joint can be constructed. The saddle may be mounted on the main base, or cut into the base piece. An infinite variety of forms of saddles are made, most of them being used in dock work, and for framing of that character where large timbers are used, as in the building of coal chutes, and the like. [Illustration: _Fig. 295. Joggle Joints._] [Illustration: _Fig. 296. Framing Joints._] JOGGLE JOINT.--This joint is used almost exclusively for brace work where great weight must be supported. The brace has a tenon, and the end must also be so arranged that it will have a direct bearing against the upright, which it braces and supports, or it may have two faces, as in the second figure, which is an exceedingly strong construction. [Illustration: _Fig. 297. Heel Joints._] [Illustration: _Fig. 298. Stub Tenon._] FRAMING JOINTS.--These are the simplest form in which two members are secured together. They are used almost wholly in rafter work, and have very few modifications. The depth of the cut, for the toe of the rafter, depends on the load to be carried, and also on the distance the end of the rafter is from the end of the horizontal member on which the rafter rests. HEEL JOINTS.--This is by far the most secure of the framing type of joints. This, if properly made, is much better than the construction shown in the previous illustration, but the difficulty is to make the rafter fit into the recesses properly. This is no excuse for failure to use, but it is on account of inability to make close fits that is accountable for lack of use. It will be seen that in case one of the heels rests against the recess, and the others do not, and the pressure is great, there is a liability to tear out the entire joint. [Illustration: _Fig. 299. Tusk Tenon._] STUB TENON.--This is another form of tenon which is made and designed to be used where it is in close proximity to another tenon, or where the mortises, if made full size, will weaken the member. The long tusk can be shortened, to suit the place where it projects, and the stub tenon on each side of the tusk may be made very short, and one side longer than the other if necessary. TUSK TENON.--Two forms of tusk construction are given. Any number of forms have been devised, all for special purposes, and designed for different kinds of woods. These shown are particularly adapted for soft woods, and the principal feature that is valuable lies in the fact that they have a number of shoulders within the mortise, each of which, necessarily adds to the strength. It should be observed that in the construction of the tusk tenon, the greatest care must be taken to have it fit the mortise tightly, and this has reference to the bottom and shoulder ends as well. [Illustration: _Fig. 300. Double Tusk Tenon._] DOUBLE TUSK TENONS.--The distinguishing difference between this and the preceding is in the tusk, which in this form of construction goes through the upright member, and is held by a cross key. The double tusk is intended for hard woods, and it is regarded as the finest, as well as the strongest, joint known. COGGED JOINTS.--This differs from the regular tenoning and mortising methods, principally because the groove or recess is in the form of an open gain. It is used where the member is to be inserted after the main structure is put together. [Illustration: _Fig. 301. Cogged Joints._] [Illustration: _Fig. 302. Anchor Joint._] ANCHOR JOINT.--This form of connection is designed for very large timbers, and where great care must be taken in making the parts fit together nicely, as everything depends on this. This style is never used where the angles are less than 45 degrees, and the depth of the gain in the timber receiving the brace is dependent on the thrust of the brace. [Illustration: _Fig. 303. Deep Anchor Joint._] The Deep Anchor Joint is an extension of the tongue of the Anchor tenon, so that it affords a greater support for the end thrust. To clearly distinguish between this and the preceding form, it might be said that the Anchor Joint is one designed to protect the member containing the gains, while the Deep Anchor Joint favors the brace, by giving it a greater power. CHAPTER XXI SOME MISTAKES, AND A LITTLE ADVICE IN CARPENTRY In the mechanical arts, workers are as likely to learn from the mistakes committed as through correct information imparted. Advice, therefore, might be considered superfluous. But there are certain things which are easily remembered and may be borne in mind while engaged in turning out any work. This chapter is not given for the purpose of calling attention to all the errors which are so common, but merely to point out a few which the boy will commit as he tries to carry out his work for the first time. One of the difficult things for any one to learn, in working with wood, is to plane the edge of a board straight and square at the same time. This is made doubly difficult if it is desired to plane it strictly to dimensions. Usually before the edge is straight it is down to the proper width desired, and it is then too late to correct any error, because further work will make it too narrow. The whole difficulty is in the holding of the plane. It matters not how rigidly it is held, and how carefully it is guarded to veer it toward one side or the other, it will be found a most difficult task. If the fore, or finishing, plane is used, and which is the proper tool for the purpose, the impression seems to be, that to square up the edge and make it cut off a thicker shaving on one side than on the other, requires that the plane should be pressed down with force, so as to make it dig in and cut a thicker shaving. When this is resorted to the board is liable to get out of true from end to end. A much better plan is to put the plane on the edge of the board true and straight. If it is too high on the edge nearest you, bring the plane over so the inside edge is flush with the inside edge of the board. Then use the fingers of the left hand as a gage to keep the plane from running over. Now, the weight of the plane in such a condition is sufficient to take off a thicker shaving at the high edge, and this will be done without any effort, and will enable you to concentrate your thoughts on keeping the plane straight with the board. The weight of the plane will make a thicker shaving on one side than on the other, and correct inequalities, provided you do not attempt to force the plane. It requires an exceedingly steady hand to hold a plane firmly for squaring up a half-inch board. Singular as it may seem, it is almost as difficult a job with a two-inch plank. In the case of the thin board the plane will move laterally, unless the utmost care is exercised; in the truing up the thick plank the constant tendency is to move the plane along the surface at a slight diagonal, and this is sure to cause trouble. It only emphasizes the fact most clearly, that to do a good job the plane must be firmly held, that it must move along the board with the utmost precision, and that it should not be forced into the wood. In smoothing down a board with the short smoothing plane, preparatory to sandpapering it, the better plan is to move the plane slightly across the grain. This will enable the bit to take hold better, and when the sandpaper is applied the course of the movement should be across the grain opposite the direction taken by the smoothing plane. It is never satisfactory to draw the sandpaper directly along in the course of the grain. Such a habit will cause the sandpaper to fill up very rapidly, particularly with certain woods. When gluing together joints or tenons, always wipe off the surplus glue with warm water taken from the glue pot. If you do not follow this advice the glue will gum up the tools and the sandpaper used to finish the work. Never try to work from opposite sides of a piece of material. Have a _work side_ and a work _edge_, and make all measurements therefrom. Mark each piece as you go along. Take a note mentally just how each piece is to be placed, and what must be done with it. The carpenter, above all others, must be able to carry a mental picture of his product. Never saw out the scribing or marking line, either in cutting or in ripping. The lines should be obliterated by the plane, when it is being finished, and not before. Make it a habit to finish off the surfaces and edges true and smooth before the ends are cut, or the mortises or tenons are made. This is one of the most frequent mistakes. No job can be a perfect one unless your material has been worked down to proper dimensions. Learn to saw across a board squarely. This may be a hard thing for the novice to do. A long, easy stroke of the saw will prevent it from running, unless too badly set or filed, and will also enable you to hold it more nearly square with the board. If you find that you invariably saw "out of true," then take some sawing lessons for your own benefit, until you can judge whether the saw is held true or not. It is better to saw up a half dozen boards in making the test than commit the error while working on a job. GLOSSARY OF WORDS USED IN TEXT OF THIS VOLUME $Acute.$ Sharp, to the point. $Adjuster.$ A tool which measures distances and relative spaces. $Æsthetic.$ The theory of taste; science of the beautiful in nature and art. $Abstract.$ That which exists in the mind only; separate from matter; to think of separately as a quality. $Alligator jaws.$ A term used to designate a pair of serrated bars which are held together in a headpiece, and capable of clamping bits between them. $Analyzed.$ Separated into its primitive or original parts. $Anchor.$ Any device for holding an object in a fixed position. $Angle dividers.$ A sort of double bevel tool so arranged that an angle can be made at the same time on both side of a base line. $Angularly disposed.$ Forming an angle with reference to some part or position. $Archivolt.$ The architectural member surrounding the curved opening of an arch. More commonly the molding or other ornaments with which the wall face of an arch is changed. $Artisan.$ One trained in some mechanic's art or trade. $Beaded.$ A piece of wood or iron having rounded creases on its surface. $Beam compass.$ A drawing compass in which the points are arranged to slide on a rod, instead of being fixed on dividers. $Belfry.$ A bell-tower, usually attached to a church. $Bevel square.$ A handle to which is pivotally attached a blade, which may be swung and held at any desired angle. $Bisected.$ To divide, mark, or cut into two portions. $Bit.$ A small tool, either for drilling, or for cutting, as a plane iron. $Braced collar.$ A form of roofing truss, in which the upper cross member is supported by a pair of angled braces. $Breast drill.$ A tool for holding boring tools, and designed to have the head held against the breast for forcing in the boring tool. $Bridle joint.$ A form for securing elements together which provides a shallow depression in one member, and a chamfered member at its end to fit therein. $Bungalow.$ A Bengalese term; originally a thatched or tiled house or cottage, single story, usually surrounded by a veranda. $Bushing.$ A substance of any kind interposed, as, for instance, a wearing surface between a mandrel and its bearing.