Fig. 247.Fig. 247.
This figure shows a common bench wholly made of material 1 inch thick, the top being 12 inches wide and 4 feet long. The legs are 14 inches high and 13 inches wide; and the side supporting railsare 3 inches wide. These proportions may, of course, be varied. You will note that the sides of the top or seat have an overhang of ½ inch on each margin.
Fig. 248.Fig. 248.
Fig. 249.Fig. 249.
This is a common, square-top stool, the seat being 12" × 12", and the legs 14 inches high. Two of the pieces forming the legs are 10 inches wide and the other two 8 inches wide, so that when thewide pieces are nailed to the edges of the narrow pieces the leg body will be 10" × 10" and thus give the seat an overhang of 1 inch around the margins.
Fig. 250.Fig. 250.
A most useful article is shown in Fig. 249. It is a blacking-box with a lid, a folding shoe rest and three compartments. The detached figure shows a vertical cross-section of the body of the box, and illustrates how the shoe rest is hinged to the sides of the box. The box itself is 14" × 16" in dimensions; the sides are 6 inches wide and the legs 5 inches in height. In order to give strength to the legs, the bottom has its corners cut out, topermit the upper ends of the legs to rest in the recesses thus formed.
Fig. 251.Fig. 251.
This is a convenient form of easel, made of four uprights. The main front uprights are of strips 5/8" × 1¼", and the rear uprights are of ½" × 1" material. A thin broomstick will serve as the pivot bar for the upper end. The rest is made of two strips, each ½" × 1", nailed together to form an L, and nails or wooden pins will serve to hold the rest in any desired position. The front uprights should be at least 5 feet long.
A simple hanging book-rack is illustrated inFig. 251. The two vertical strips are each 4 inches wide, 1 inch thick and 4 feet long. Four shelves are provided, each ¾ inch thick, 9 inches wide and 4 feet long. Each shelf is secured to the uprights by hinges on the upper side, so as to permit it to be swung upwardly, or folded; and below each hinge is a triangular block or bracket, fixed to the shelf, to support it in a horizontal position.
Fig. 252.Fig. 252.
A sad-iron holder, or bookcase, shown in Fig. 252, is another simple form of structure. It may be sufficiently large to serve as a standing case by having the uprights at the ends serve as legs, or the uprights may have holes at their upperends, by means of which it can be suspended on a wall. As shown, it is 30 inches long from bottom to top, and 20 inches wide. The shelves are 8 inches wide. All the material is, preferably, ¾-inch stock.
Fig. 253.Fig. 253.
Fig. 253 shows a wood-box, or it may readily be adapted for coal. For wood it should be 2 feet long, 1 foot 8 inches wide and 1 foot 10 inches high. It will, of course, be made of such dimensions as to suit the wood to be stored in it, and both the flat-top as well as the sloping portion of the top should be hinged, so that the entire top can be opened for filling purposes.
Fig. 254.Fig. 254.
Fig. 255.Fig. 255.
A pair of parallel bars is shown in Fig. 254. The dimensions of this will vary, and be dependent on the size of the boy intending to use it; but a size best adapted is to make the posts 3 feet high,and the distance between the bars 16 inches. This gives ample room for the exercises required. The length between the posts along the bars should be at least 5 feet. The entire structure can be made of soft wood, except the bars, which should be of hard, rigid wood. The posts can be made of 2" × 2" material, and the braces 2" × 1". The basepieces, both longitudinal and transverse, should also be of 2" × 2" material.
Fig. 256.Fig. 256.
Fig. 257.Fig. 257.
Fig. 255 represents a mission type of writing desk for a boy's use. All the posts, braces and horizontal bars are of 2" × 2" material, secured to each other by mortises and tenons. The legsare 27 inches high up to the table top, and the narrow shelf is 12 inches above the top. The most convenient size for the top is 26" × 48". The top boards may be 1 inch thick and the shelf the same thickness, or even ¾ inch. It is well braced and light, and its beauty will depend largely on the material of which it is made.
Fig. 258.Fig. 258.
The screen (Fig. 256) represents simply theframework, showing how simple the structure is. The bars are all of 1½" × 1½" material, secured together by mortises and tenons.
Fig. 257 represents a mission chair to match the desk (Fig. 255), and should be made of the same material. The posts are all of 2" × 2" material. The seat of the chair should be 16 inches, and the rear posts should extend up above the seat at least 18 inches.
Fig. 259.Fig. 259.
Fig. 260.Fig. 260.
Fig. 261.Fig. 261.
Fig. 258 is a good example of a grandfather's clock in mission style. The framework only is shown. The frame is 12" × 12", and 5 feet high, and made up of 2" × 2" material. When neatly framed together, it is a most attractive article offurniture. The top may be covered in any suitable way, showing a roof effect. The opening for the dial face of the clock should be at one of the gable ends.
A more pretentious bookcase is shown in Fig. 259, in which the frame is made up wholly of 2" × 2" material. The cross-end bars serve as ledges to support the shelves. This may be lined interiorly and backed with suitable casing material, such as Lincrusta Walton, or fiber-board, and the front provided with doors. Our only object is to show the framework for your guidance, and merely to make suggestions as to structural forms.
Fig. 262.Fig. 262.
Another most serviceable article is a case for a coal scuttle (Fig. 260). This should be made of 1-inch boards, and the size of the door, which carries the scuttle shelf, should be 12" × 16" in size. From this you can readily measure the dimensionsof the case itself, the exterior dimensions of which are 15" × 20", so that when the 1-inch top is placed on, it will be 21 inches high. The case from front to rear is 12 inches, and the shelf above the top is 11 inches wide, and elevated 10 inches above the top of the case. This is a most useful box for culinary articles, if not needed for coal, because the ledge, used for the coal scuttle, can be used to place utensils on, and when the door is opened all the utensils are exposed to view, and are, therefore, much more accessible than if stored away in the case itself.
Fig. 263.Fig. 263.
A mission armchair. Fig. 261 is more elaborate than the chair shown in Fig. 257, but it is the same in general character, and is also made of 2" × 2" stock. The seat is elevated 16 inches from the floor, and the rear posts are 28 inches high.The arms are 8 inches above the seat. A chair of this character should have ample seat space, so the seat is 18" × 18".
The dog house (Fig. 262), made in imitation of a dwelling, is 24 inches square, and 18 inches high to the eaves of the roof. The opening in front is 8" × 10", exclusive of the shaped portion of the opening.
Fig. 264.Fig. 264.
Fig. 265.Fig. 265.
Fig. 263 shows a simple and easily constructed settee with an under shelf. The seat is 16 inches from the floor and 24 inches wide. The back extends up 24 inches from the seat. The lower shelf is midway between the floor and seat, andis 19 inches wide. This may or may not be upholstered, dependent on the character of the material of which it is made. If upholstered, the boards may be of second-class material, preferably of pine or other light, soft wood.
A towel rack (Fig. 264) is always a needed article in the kitchen. The roller may be an old curtain roller cut down to 18 inches in length. The top piece is 2½ inches wide and 21 inches long. The vertical bars are each 1½ inches wide and 9 inches long. The brackets are 1½ inches wide and made of ¾-inch material.
Fig. 265 represents the framework of a sofa, the seat of which is 16 inches high, the front posts up to the arm-rests 24 inches, and the rear posts 38 inches. From front to rear the seat is 18 inches. The posts are of 3" × 3" material. This makes a very rigid article of furniture, if mortised and tenoned and properly glued. The seat is 6 feet long, but it may be lengthened or shortened to suit the position in which it is to be placed. It is a companion piece to the chair (Fig. 261).
In the foregoing chapters we have referred the reader to the simple tools, but it is thought desirable to add to the information thus given, an outline of numerous special tools which have been devised and are now on the market.
Bit and Level Adjuster.—It is frequently necessary to bore holes at certain angles. This can be done by using a bevel square, and holding it so one limb will show the boring angle. But this is difficult to do in many cases.
Fig. 266. Bit and Square level.Fig. 266. Bit and Square level.
This tool has three pairs of V slots on its back edges. The shank of the bit will lie in these slots, as shown in Fig. 266, either vertically, or at an angle of 45 degrees, and boring can be done with the utmost accuracy. It may be attached to a Carpenter's square, thus making it an accurate plumb or level.
Miter Boxes.—The advantages of metal miter boxes is apparent, when accurate work is required.
The illustration, Fig. 267, shows a metal tool of this kind, in which the entire frame is in one solid casting. The saw guide uprights are clamped in tapered sockets in the swivel arm and can be adjusted to hold the saw without play, and this will also counteract a saw that runs out of true, due to improper setting or filing.
Fig. 267. Metal Miter Box.Fig. 267. Metal Miter Box.
A second socket in the swivel arm permits the use of a short saw or allows a much longer stroke with a standard or regular saw.
The swivel arm is provided with a tapering index pin which engages in holes placed on the underside of the base. The edge of the base is graduated in degrees, as plainly shown, and the swivel arm can be set and automatically fastened at any degree desired.
Fig. 268. Parts of Metal Miter Box.Fig. 268. Parts of Metal Miter Box.
The uprights, front and back are graduated in sixteenths of inches, and movable stops can be set, by means of thumb-screw to the depth of the cut desired.
Figure 268 shows the parts of the miter box, in which the numbers designate the various parts: 101 is the frame; 102 the frame board; 104 frameleg; 106 guide stock; 107 stock guide clamp; 109 stock guide plate; 110 swivel arm; 111 swivel arm bushing; 112 swivel bushing screw; 113 index clamping lever; 115 index clamping lever catch; 116 index clamping lever spring; 122 swivel complete; 123 T-base; 124½ uprights; 126 saw guide cap; 127 saw guide cap plate; 132 saw guide tie bar; 133 left saw guide stop and screw; 134 right side guide stop and screw; 135 saw guide stop spring; 136 saw guide cylinder; 137 saw guide cylinder plate; 138 trip lever (back); 139 trip lever (front); 141 leveling screw; 142 trip clamp and screw; 146 T-base clamp screw.
Fig. 269. Angle Dividers.Fig. 269. Angle Dividers.
Angle Dividers.—This is another tool, which does not cost much and is of great service to thecarpenter in fitting moldings where they are applied at odd angles.
To lay out the cut with an ordinary bevel necessitates the use of dividers and a second handling of the bevel, making three operations.
The "Odd Job" Tool.—A most useful special tool, which combines in its make-up a level, plumb try-square, miter-square, bevel, scratch awl, depth gage, marking gage, miter gage, beam compass, and a one-foot rule. To the boy who wishes to economize in the purchase of tools this is an article which should be obtained.
Fig. 270. "Odd Job" Tool.Fig. 270. "Odd Job" Tool.
Figure 270 shows the simplicity of the tool, and how it is applied in use.
Bit Braces.—These tools are now made with somany improved features that there is really no excuse for getting poor tools.
The illustrations show merely the heads and the lower operating parts of the tools. Fig. 271 shows a metal-clad ball-bearing head, so called, as its under side is completely encased in metal securely screwed to the wood and revolving against the ball thrust bearing.
D represents a concealed ratchet in which the cam ring governs the ratchet, and, being in line with the bit, makes it more convenient in handling than when it is at right angles. The ratchet parts are entirely enclosed, thus keeping out moisture and dirt, retaining lubrication and protecting the users' hands.
The ratchet mechanism is interchangeable, and may be taken apart by removing one screw. The two-piece clutch, which is drop forged, is backed by a very strong spring, insuring a secure lock. When locked, ten teeth are in engagement, while five are employed while working at a ratchet. It has universal jaws (G) for both wood and metal workers.
In Fig. 272, B represents a regular ball bearing head, with the wood screw on the large spindle and three small screws to prevent its working loose. This also has a ball thrust. E is the ratchet box, and this shows the gear teeth cut on the extraheavy spindle, and encased, so that the user's hands are protected from the teeth.
The interlocking jaws (H), which are best for taper shanks, hold up to No. 2 Clark's expansion, and are therefore particularly adapted for carpenter's use.
Fig. 271. Types of Bit Braces. Fig. 272. Types of Bit Braces. Fig. 273. Types of Bit Braces.Fig. 271. Fig. 272. Fig. 273.Types of Bit Braces.
In Fig. 273 the plain bearing head (C) has no ball thrust. The head is screwed on the spindle andheld from turning off by two small screws. The open ratchet (F) shows the gear pinned to the spindle and exposed. This has alligator jaws (J), and will hold all ordinary size taper shank bits, also small and medium round shank bits or drills.
Fig. 274. Fig. 275. Fig. 276.Fig. 274. Fig. 275. Fig. 276.Steel Frame Breast Drills.
Steel Frame Breast Drill.—These drills are made with both single and double speed, each speed having three varieties of jaws. The single speed is very high, the ratio being 4½ to 1, which makesit desirable to use for small drills, or for use in wood.
A level is firmly set in the frames of these tools to assist the user to maintain a horizontal position in boring. Each of the forms shown has a ball thrust bearing between the pinion and frame. The breast plate may be adjusted to suit and is locked by a set screw. The spindle is kept from turning while changing drills, by means of the latch mounted on the frame, and readily engaging with the pinion. The crank is pierced in three places so that the handle can be set for three different sweeps, depending on the character of the work.
Figure 274 has a three jaw chuck, and has only single speed. Figure 275 has an interlocking jaw, and is provided with double speed gearing. Figure 276 has a universal jaw, and double speed.
Planes.—The most serviceable planes are made in iron, and it might be well to show a few of the most important, to bring out the manner employed to make the adjustments of the bits.
In order to familiarize the boy with the different terms used in a plane, examine Figure 277. The parts are designated as follows: 1A is the double plane iron; 1 single plane iron; 2 plane iron cap; 3 cap screw; 4 lever cap; 5 lever cap screw; 6 frog complete; 7 Y adjusting lever; 8 adjusting nut; 9 lateral adjusting lever; 11 plane handle;12 plane knob; 13 handle bolt and nut; 14 knob bolt and nut; 15 plane handle screw; 16 plane bottom; 44 frog pin; 45 frog clamping screw; 46 frog adjusting screw.
Fig. 277. Details of Metal Plane.Fig. 277. Details of Metal Plane.
Rabbeting, Matching and Dado Planes.—Figure 278 shows a useful form of plane for the reason that it is designed to receive a variety of irons, adapted to cut rabbets.
The detached sections of Fig. 278 show the various parts, as well as the bits which belong to it. 1, 1 represent the single plane irons; 4 the lever cap; 16 the plane bottom, 50 the fence; 51 the fence thumb screw; 61 the short arm; 70 the adjustabledepth gage; 71 the depth gage which goes through the screw; and 85 the spurs with screws.
Molding and Beading Plane.—A plane of the character shown in Fig. 279 will do an immense variety of work in molding, beading and dado work, and is equally well adapted for rabbeting, for filletsters and for match planing. The regular equipment with this tool comprises fifty-two cutters.
Fig. 278. Rabbet, Matching and Dado Plane.Fig. 278. Rabbet, Matching and Dado Plane.
As shown in Fig. 279, the plane has a main stock (A), which carries the cutter adjustment, a handle, a depth gage, a slitting gage, and a steel bottom forming a bearing for the other end of the cutter, and slides on arms secured to the main stock.
This bottom can be raised or lowered, so that, in addition to allowing the use of cutters of differentwidths, cutters can be used having one edge higher or lower than the edge supported in the main stock.
Fig. 279. Molding and Beading Plane.Fig. 279. Molding and Beading Plane.
The auxiliary center bottom (C), which can be adjusted for width or depth, fulfils the requirement of preventing the plane from tilting and gouging the work. The fence D has a lateral adjustment by means of a screw, for extra fine work.The four small cuts in the corners show how the bottoms should be set for different forms of cutters, and the great importance of having the fences adjusted so that the cutters will not run.
The samples of work illustrated show some of the moldings which can be turned out with the plane.
Fig. 280. Dovetail Tongue and Groove Plane.Fig. 280. Dovetail Tongue and Groove Plane.
Dovetail Tongue and Groove Plane.—This is a very novel tool, and has many features to recommend it. Figure 280 shows its form, and how it is used. It is designed to make the dovetailed tongue as well as the groove.
It will cut any size groove and tongues to fit with sides of twenty degrees flare, where the widthof the neck is more than one-quarter of an inch thick, and the depth of the groove not more than three-quarters of an inch. The tongue and groove are cut separately, and can be made with parallel or tapering sides. The operation of the plane is very simple.
Fig. 281.Fig. 282.Fig. 281.Fig. 282.
Fig. 281.
Fig. 282.
Router Planes.
Router Planes.—This is a type of plane used for surfacing the bottom of grooves or other depressions parallel with the general surface of the work.
The planes are made in two types, one, like Fig. 281, which has a closed throat, and the other, Fig. 282, with an open throat. Both are serviceable, but the latter is preferable. These planes willlevel off bottoms of depression, very accurately, and the tool is not an expensive one.
Door Trim Plane.—This is a tool for making mortises for butts, face plates, strike plates, escutcheons, and the like, up to a depth of 5/16, and a width of 3 inches. The principal feature in the plane is the method of mounting the cutter, which can be instantly set to work from either end of the plane or across it.
Fig. 283. Door Trim Plane.Fig. 283. Door Trim Plane.
The cutter, as shown in Fig. 283, is cushioned by a spring which prevents taking a heavier chip than can be easily carried. A fence regulates the position of the cut and insures the sides of the cut being parallel. The depth of the cut is governed by a positive stop. By removing the fence and locking the cutter post with the thumb screw, instead of using the spring, a very superior router plane is obtained.
The chapter on Bridge Building gives some suggestions as to form of trusses, the particular types there shown being principally for wide spans. Such trusses were made for one purpose only, namely, to take great weight, and they were, as a consequence, so constructed as to provide strength.
But a roofing truss, while designed to hold the accumulated materials, such as snow and ice, likely to be deposited there, is of such a design, principally, so as to afford means of ornamentation. This remark has reference to such types as dispense with the cross, or tie beam, which is the distinguishing feature in bridge building.
The tie beam is also an important element in many types of trusses, where ornamentation is not required, or in such structures as have the roofed portion of the buildings enclosed by ceiling walls, or where the space between the roofs is used for storage purposes.
In England, and on the Continent of Europe, are thousands of trusses structured to support the roofs, which are marvels of beauty. Some of themare bewildering in their formation. The moldings, beaded surfaces, and the carved outlines of the soffits, of the arches, and of the purlins, are wonderful in detail.
The wooden roof of Westminster Hall, while very simple in structure, as 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.
Fig. 284. Gambrel Roof.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.
Fig. 285. Purlin Roof.Fig. 285. Purlin Roof.
The Purlin Roofis 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.
Fig. 286. Princess Truss.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 maycall 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 theArched, orCambered, Tie Beam Truss. It is a very old type, samples of which have been found which take it back to a very remote age.
Fig. 287. Arched, or Cambered, Tie Beam.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 Mansardis what may be called a double-mounted roof, and it will be seen how it wasevolved 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.
Fig. 288. The Mansard.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 theScissors 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.
Fig. 289. Scissors Beam.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 thisarrangement 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.
Fig. 290. Braced Collar Beam.Fig. 290. Braced Collar Beam.
The Rib and Collar Truss, Fig. 291, is the firstimportant structural arrangement which permitted the architect to give full sway to embellishment. The inwardly-projecting members (A, A) are calledHammer 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.
Fig. 291. Rib and Collar Truss.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.
Fig. 291½. Hammer Beam Truss.Fig. 291½. Hammer Beam Truss.
The acme of all constructions, in which strength, beauty, and capacity for ornamentation are blended, is theHammer 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.
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.
Fig. 292. Bridle Joints.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 structuralforms, but principally with such as are used in heavy building work, and in cases where neither fish plates nor scarfing will answer the purpose.
Fig. 293.Fig. 293. Spur Tenon.Fig. 294.Fig. 294. Saddle Joints.
Fig. 293. Spur Tenon.
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 partsare 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.
Fig. 295.Fig. 295. Joggle Joints.Fig. 296.Fig. 296. Framing Joints.
Fig. 295. Joggle Joints.
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 endmust 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.
Fig. 297. Heel Joints.Fig. 297. Heel Joints.
Fig. 298. Stub Tenon.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.
Fig. 299. Tusk Tenon.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.