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CARPENTRY
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CARPENTRY , the See also:art and See also:work of a See also:carpenter (from See also:Lat. carpentum, a See also:carriage), a workman in See also:wood, especially for See also:building purposes. The labour of the See also:sawyer is applied to the See also:division of large pieces of See also:timber or logs into forms and sizes to suit the purposes of the carpenter and joiner. His working-See also:place is called a sawpit, and his most important See also:tool is a See also:pit-saw. A See also:cross-cut saw, axes, See also:dogs, files, compasses, lines, lampblack, blacklead, See also:chalk and a See also:rule may also be regarded as necessary to him. But this method of sawing timber is now only used in remote See also:country places, and in See also:modern practice logs, &c., are converted into planks and small pieces at saw-See also:mills, which are equipped with modern machinery to drive all kinds of circular saws by See also:electricity, See also:steam or See also:gas. Carpentry or carpenters' work has been divided into three See also:principal branches— descriptive, constructive and See also:mechanical. The first shows the lines or method for forming every See also:species of work by the rules of See also:geometry; the second comprises the practice of reducing the timber into particular forms, and joining the forms so produced in such a way as to make a See also:complete whole according to the intention or See also:design; and the third displays the relative strength of the timbers and the strains to which they are subjected by their disposition. Here we have merely to describe the See also:practical details of the carpenter's work in the operations of building. He is distinguished from the joiner by his operations being directed to the See also:mere See also:carcass of a building, to things which have reference to structure only. Almost every-thing the carpenter does to a building is absolutely necessary to its stability and efficiency, whereas the joiner does not begin his operations until the carcass is complete, and every See also:article of joiners' work might at any See also:time be removed from a building without undermining it or affecting its most important qualities. Certainly in the practice of building a few things do occur regarding which it is difficult to determine to whose immediate See also:province they belong, but the distinction is sufficiently broad for See also:general purposes. The carpenter frames or combines See also:separate pieces of timber by scarfing, notching, cogging, tenoning, pinning and wedging, &c. The tools he uses are the rule, See also:axe, See also:adze, saws, See also:mallet, hammers, See also:chisels, gouges, augers, pincers, set squares, See also:bevel, compasses, gauges, level, plumb rule, See also:jack, trying and smoothing planes, See also:rebate and moulding planes, and gimlets and wedges• See also:plan) FIG. 2.-Fished See also:Joint. plan plan See also:FIGS. 3, 4 and 5.-See also:Scarf See also:Joints. The carpenter has little labour to put on to the stuff; his See also:chief work consists in fixing and cutting the ends of timbers, the labour in preparing the timber being done by machinery. Joints.—The joints in carpentry are various, and each is designed according to the thrust or See also:strain put upon it. Those principally used are the following: See also:lap, fished, scarf, notching, cogging, dovetailing, See also:housing, halving, mortice and tenon, stub JI01Pi See also:iron el¢valion f tez.s -bolts :II it tenon, dovetailed tenon, tusk tenon, joggle, bridle, foxtail wedging, See also:mitre, birdsmouth, built-up, dowel. Illustrations are given of the most useful joints in general use, and these, together with the descriptions, will enable a See also:good See also:idea to be formed of their respective merits and methods of application. The lapped joint (fig. 1) is used for temporary structures in lengthening timbers and is secured with iron straps and bolts; a very See also:common use of the lap joint is seen in scaffolding secured with cords and wedges. The fished joint (fig. 2) is used for lengthening beams and is constructed by butting the ends of two pieces of timber together with an iron See also:plate on See also:top and bottom, and bolting through the timber; these iron connecting-plates are usually about 3 ft. See also:long and 4 in. and i in. in thickness. This joint provides a good and cheap method of accomplishing its purpose. The scarf joint (figs. 3, 4 and 5) is used for lengthening beams, and is made by cutting and notching the ends of timbers and lapping and fitting and bolting through. This method cuts into the timber, but is very strong and neat; in addition for extra strong work an iron See also:fish-plate is used as in the fished joint. The ends of See also:floor joints and rafters are usually notched (fig. 6) over plates to obtain a good bearing and bring them to the re- quired levels. Where one timber crosses another as in pur- lins, rafters, wood floor girders, plates, &c., both timbers are notched so as to See also:fit over each other; this See also:cog- ging (fig. 7) serves instead of fastenings. The timbers are held together with a spike. In this way they are not weakened, and the joint is a very good one for keeping them in position. Dovetailing (fig. 8) is used for connecting angles of timber together, such as See also:lantern curbs or linings, and is the strongest See also:form. When an end of timber is let entirely into another timber it is said to be housed (fig. 9). Where timbers cross one another and require to be flush on one or both faces, sinkings are cut in each so as to fit over each other (halving); these can either be square (fig. 1o), bevelled (fig. 11) or See also:dove- tailed sinkings (fig. 12). The end of one piece of timber cut so as to leave a third of the thickness forms a tenon, and the piece of timber which is to be joined to it has a mortice or slot cut through it to receive the tenon; the two are then wedged or pinned with wood pins (fig. 13). A stub tenon or joggle (fig. 14) is used for fixing a See also:post to a See also:sill; a sinking is cut in the sill and a tenon is cut on the See also:foot of the post to fit into the sinking to keep the post from sliding. The purpose of a dove-tailed tenon (fig. 15) is to hold two pieces of wood together with mortice and tenon so that it can be
lo.—Halving.
taken apart when necessary. The tenon is cut dovetail shape, and a long mortice permits the wide See also:part of the tenon to go through, and it is secured with wood wedges. Where the floor joists or rafters are trimmed See also:round fires, See also:wells, &c., the tusk tenon joint (fig. 16) is used for securing the See also:trimmer See also:joist. It is formed by cutting a tenon on the trimmer joist and passing it through the See also:side of the trimming joist and fixing it with a wood See also: But the tenon does not go through the full thickness of the timber; and also on the end of the tenon are inserted two wedges, so that when the tenon is driven See also:home the wedges split it and See also:wedge tightly into the mortice. This joint is used mostly in See also:joinery. The mitre is-a universal joint, used for connecting angles of timber as in the See also:case of picture frames. Built-up joints involve a See also:system of lapping and bolting and fishing, as in the case of temporary structures, for large spans of centering for See also:arches, and for See also:derrick See also:cranes. Dowels are usually 3 or 4 in. long and driven into a circular hole in the foot of a See also:door See also:frame or post; the other end is let into a hole in the sill (fig. 19).
Centering.—Centering is temporary timber or framing erected so as to carry See also:concrete floors or arches of See also:brick or See also: 21); it is only 44. in. wide on the See also:soffit or See also:bed, and is generally cut out of a piece of 3 or 4 in. stuff, the top edge being made circular to the shape of the arch. It is kept EI~ic See also:lion c5ecli0h FIG. 2I. in position whilst the arch is setting with struts from ground or sills and is nailed to the reveals, a couple of cross traces being wedged between. In the case of a semicircular or elliptical arch with 43- in. soffit this turning piece would be constructed of ribs cut out of 4 in. stuff with ties and braces. Or the ribs could be cut out of 1 in. stuff, in which case there must be one set of ribs outside and one inside secured with ties and braces; each set of ribs when formed of thin stuff is made of two thicknesses nailed together so as to lap the joints. For spans up to 15 ft. the thin ribs would be used, and for spans above 15 ft. ribs out of 4 in. stuff and upwards. For arches with 9 in. soffit and upwards, whether segmental or semicircular or elliptical, the centres are formed with the thin ribs and laggings up to 15 ft. span; above 15 ft. with 4 in. ribs and upwards (fig. 22). The See also:lower member of centres is called the tie, and is fixed so as to tie the extremities together and to keep the centre from spreading. Where the span is See also:great, these ties, instead of being fixed straight, are given a rise so as to allow for See also:access or See also:traffic underneath. Braces are necessary to support the ribs from buckling in, and must.be strong enough and so arranged as to withstand all stresses. Laggings are small pieces or strips of wood nailed on the ribs to form the See also:surface on which to build the arch, and are spaced 1 in. apart for See also:ordinary arches; for gauged arches they are nailed See also:close together and the joints planed off. When centres are required to be taken down, the wedges upon which the centre rests are first removed so as to allow the arch to take its bearing gradually. Centres for brick sewers and vault arching are formed in the same way as previously mentioned, with ribs and laggings, but the thickness of the timbers depends upon the See also:weight to be carried. Floors.—For ordinary residential purposes floors are chiefly constructed of timber. tip to about the See also:year 1895 nearly every modern building was constructed with wood joists, but because of See also:evidence adduced by See also:fire See also:brigade experts and the serious fires that have occurred fire-resisting floors have been introduced. These consist of steel girders and joists, filled in with concrete or various patented brick materials in accordance with such by-See also:laws as those passed by the See also:London See also:County See also:Council and other authorities, The See also:majority of the floors of public turning pfzcz cCtlOfl See also:wind ---;1 r~~~g~~~~~~ffffffo Concrete. buildings, factories, See also:schools, and large residential flats are now constructed of fire-resisting materials. There are two descriptions of flooring, single and See also:double. Single flooring (fig. 23) consists of one See also:row of wood joists resting on a See also:wall or See also:partition at each end without any inter- mediate support, and receiving the floor boards on the upper surface and the See also:ceiling on the underside. Joists should never be less than 2 in. thick, or they are liable to split when the floor brads are driven in; the thickness varies .dowelled heading joint from 2 to 4 in. and the See also:depth from 5 to I I in. (see By-laws, below); the distance between each joist is usually 12 in. in the clear, but greater strength is obtained in a floor by having deep joists and placing them closer together. These floors are made See also:firm and prevented from buckling by the use of strutting as mentioned hereafter. The efficiency of single flooring is materially affected by the See also:necessity which constantly occurs in practice of trimming round fireplaces and flues, and round well holes such as lifts, staircases, &c. Trimming is a method of supporting the end 'of a joist by tenoning it into timber See also:crossing it; the timber so tenoned is called the trimmer joist, and the timber morticed for the tenon of the trimmer is called the trimming joist, while the intermediate timbers tenoned into the trimmer are known as the trimmed b I II ::; st- i~~ wattplabzoniron co y i ii/immo/offmms,mmamfoie/4 FIC. zg.—Double Floor, with Steel See also:Borders. joists. This system has to be resorted to when it is impossible to get a bearing on the wall. A trimmer requires for the most part to be carried or supported at one or both ends by the trimming joists, and both the trimmer and the trimming joists are necessarily made stouter than if they had to See also:bear no more than their own See also:share of the stress. In the usual practice the trimmer and trimming joists are r in. thickerthan the common joists, but there are See also:special regulations and by-laws set out in the various districts and boroughs (see By-laws, below) to which See also:attention must be given. The principal objection to single flooring is that the See also:sound passes through from floor to floor, so that, in some cases,conversation in one See also:room can almost be understood in another. To stop the sound from passing through floors the remedy is to pug them (fig. 24). This consists in using rough boarding resting on fillets nailed to the sides of the joists about See also:half-way up the depth of the joists, and then filling in on top of the boarding with slag See also:wool usually 3 in. thick. Also to further prevent sound from bindar passing through floors the flooring should be tongued and the ceiling should have a good thick floating coat; in poor work the stuff on ceilings is very stinted. In days gone by, ceiling joists were put at right angles to the floor joists, but this took up See also:head room and was costly, and the arrangement is obsolete. Double flooring (fig. 25) consists of single See also:fir joists trimmed into steel girders; in earlier times a double floor consisted of fir joists called binding, bridging and ceiling joists, but these are very little used now and the single fir floori g joists and steel girders have taken their place. Steel girders span from wall to wall, and on their flanges are bolted wood plates to receive the ends of the single joists which are notched over plates and run at right angles to the Single flooring. girders (fig. 26). The See also:bearings of the joists on the wall also rest on wall plates, so as to get a level bed, and are some-times notched over them. Wall plates, which are usually 4 in. X 3 in. and are bedded on walls in motar, take the ends of joists and distribute the weight along the wall. The plates bolted on the side of girders are of sizes to suit the width of the flanges. The See also:medieval floor (fig. 27) consisted of the framed floor with wood girders, binding, bridging and ceiling joists, and the under-side of all the timbers was usually wrought, the girders and binders being boldly moulded and the other timbers either square or stop chamfered. Flooring is strengthened by the use of strutting, either See also:herring-See also:bone (fig. 28) or solid (fig. 29). Herring-bone strutting consists of two pieces of timber, usually 2 in. X 2 in., fixed diagonally between each joist in continuous rows, the rows being about 6 ft. apart. Solid strutting consists of 1i in. boards, nearly the same depth as the joists and fitted tightly between the joists, and nailed in continuous rows 6 ft. apart. Where heavy weights are likely to be put on floors long bolts are passed through the centre of joists at the side of strutting; since this draws the strutting tightly together and does not produce any forcing stress on the walls, it is undoubtedly the best method. Floors are usually constructed to carry the following loads (including weight of floor) Residences, 14 cwt. per foot super of floor space. Public buildings, i4 cwt. per foot super of floor space. Factories, 22 to 4 cwt. per foot super of floor space. See also:Local By-laws.—With regard to floor joists in domestic buildings, the following are required in the See also:Hornsey See also:district, in the See also:north of London. The size of every common bearing floor joist up to 3 ft. long in clear shall be 3 in. X 22 in.; from 3 ft. to 6 ft. in clear it shall be 42 in. X 3 in. ; from 6 ft. to 8 ft., 62 in. X 22 in. ; from 8 ft. to 12 ft., 7 in.X22 in., and so on according to the clear span. The Hornsey by-laws with regard to trimmers are as follows:—A trimmer joist shall not receive more than six common joists, and the thickness of a trimming joist receiving a trimmer at not more than 3 ft. from one end and of every trimmer joist shall be 1th of an See also:inch greater than the thickness for a common joist of the same bearing for every common joist carried by a trimmer. For example, if the common joists are 7 in. X22 in. and the trimmer has six joists trimmed into same, the size of trimmer would have to be 7 in. X34 in. The Hornsey council also requires that the floor boards shall not be less than '-gths of an inch thick. There is little difference in the requirements of the various localities. For example, the regulations of the See also:Croydon council require that every common bearing joist for lengths up to 3 ft. 4 in. in clear shall be 3 in. X22 in.; for lengths between 3 ft. 4 in. and 5 ft. 4 in., 4 in. X2 in.; for lengths between 5 ft. 4 in. and 7 ft. 4 in., 4 in. X3 in.; and so on according to the clear span. The Croydon by-laws with regard to trimmers are as follows:—A trimmer joist shall not receive more than six common joists, and the thickness of a trimming joist shall be 12 in. thicker than that for common joists of the same bearing, and the thickness of a trimmer joist shall be 4 in. thicker for every joist trimmed into same than the common joist. For example, if the common joists are 4 in. X3 in. the trimming joists would have to be 4 in. X42 in., and the trimmer joist would have to be 4 in. X42 in. Partitions.—Partitions are screens used to See also:divide large floor spaces into smaller rooms and are sometimes constructed to carry the floors above by a system of trussing. They are built of various materials; those in use now are common See also:stud partitions, bricknogged partitions, and solid See also:deal and hardwood partitions, 4 in. brick walls or bricks laid on their sides, so making a 3 in. partition, and various patent partitions such as See also:coke See also:breeze concrete or hollow brick partitions (see See also:BRICKWORK), iron and See also:wire partitions, and See also:plaster slab partitions (see PLASTER-WORK). There are two kinds of stud or See also:quarter partitions, common and trussed. Common partitions (fig. 3o) simply See also:act as a See also:screen to divide Partition .7Pzclioo one room from another, and do not carry any weight. They weigh about 25 lb per foot superficial including plastering on both sides, and are composed of 4 in. X 3 common panitions. in. head and sill and 4 in. X 2 in. upright studs; 4 in. X 2 in. nogging pieces are fitted between the studs to keep them from bending in, and are placed parallel with the head,. usually 4 ft. apart. Where door-openings occur in these partitions the studs next the opening are 4 in. X 3 in. Should the floor boards have been laid, the sill of the partition would be laid See also:direct on them, but if the partitions are erected at the time of building the structure the sill should either rest directly over a joist, if parallel with it, or at right angles to the joists; should the position of the sill come between two joists, that is, parallel with them, then See also:short pieces called bridging pieces of 4 in. X 2 in. stuff are wedged between the two joists and nailed to carry the sill.
Trussed partitions (fig. 31) are very similar to the last, but they are so built as to carry their mil% weight and also
to support floors, and in addition have braces; the p rrssed partitions.
head and sill are larger, and calculated according to
the clear bearing and the weight put upon them. There are
two forms of trussing, namely, See also:queen post (fig. 32) and See also: 31.—Trussed Partition.
I1
in a public building the London Building Act requires them to be of 2 in. hardwood, with only small panels of fire-resisting See also:glass.
Timber Work.—Half timber work consists of a framework of timber; the upper storeys of suburban arid country residences are often thus treated, and the spaces between the timbers are filled in with brickwork and plastered inside, and rough See also:cast outside, though sometimes tiles are hung on the outside. In some instances in country places there is no filling between the timbers, and both sides are See also:lath and plastered, and in others the timbers are solid, or facing pieces are simply plugged to the walls, the joints being pinned with hardwood pins. Half timber work (fig. 34) well designed has a very pleasing, homely and rural effect. The best and most durable wood to use is See also:English See also:oak worked smooth on the See also:external See also:face and usually painted; the by-laws of various authorities differ considerably as to the method of construction and in the restrictions as to its use. Some very See also:fine See also:early examples are to be seen in See also:England, as at See also:Holborn Bars, London, in the old parts of See also:Bristol, and at Moreton Old See also: 34.-Half Timber Construction. At the See also:garden See also:city of Letchworth, in See also:Hertfordshire, there are a few timber-framed bungalows (erected about 1904 and originally intended to be used as See also:week-end cottages), the outsides of which are covered with sheet iron and painted. Other instances of the temporary use of this See also:kind of building are found in soldiers' See also:barracks, offices and chapels. In See also:America and the See also:British colonies this class of building is very largely erected on the outskirts of the cities. In See also:American practice in framing the walls of wooden buildings two distinct methods are used and are distinguished as " braced " and " See also:balloon." The Braced (fig. 35) was the only kind in use previous to about the year 185o. In this method of framing the sills, posts, girts and plates are made of heavy timber morticed and pinned together and braced with 4 in. X 4 in. or 4 in. X 6 in. braces and common studding. To frame a building in this way it is necessary to cut all the pieces and make all the mortice holes on the ground, and then fit them together and raise a whole side at a time or at least one See also:storey of it. The common studs are only one storey high. The Balloon frame (fig. 36) is composed of much smaller scantlings and is more rapidly erected and less expensive, The method is to first See also:lay the sill, generally 4 in. X 6 in., halved at the angles. After the floor is laid, the corner posts, usually 4 in. X 6 in., are erected and temporarily secured in place with the aid of stays. The common studs are then set del-nil at D lower floors of buildings. Solid wood partitions are used in offices and class-rooms of schools, the upper portions usually being glazed; where these partitions enclose a See also:staircase 5eaclion FIG. 33.-King Post Trussed Partition. up and spiked to the sill, and a temporary See also:board nailed across their face on the inside. These common studs are , the full height from sill to roof plate, and the second tier of floor joists are supported by notching a l t in. X 7 in. board, called a false girt or ribbon, into their inside edge at the height to receive the floor joists. The ends of the joists are also placed against a stud and spiked. The tops of the studs are cut to a See also:line, and a 2 in. X 4 in. plate is spiked on top, an additional 2 in. X 4 in. plate being placed on the top of the last breaking joint. Should the studs not be long enough to reach the plate, then short pieces are fished on with pieces of wood spiked on both sides. The See also:diagram shows a portion of the framework of a two-storey house I cut or looped), and used as a floor covering. Other floor constructed in the manner described. In the balloon frame 1 coverings are and have been made also without such a tufted the timbers are held together entirely by nails and spikes, surface, and of these some are See also:simple See also:shuttle-See also:woven materials thus permitting them to be put up rapidly. The studs are doubled where windows or openings occur. In both these methods See also:dwarf brick See also:foundations should be built, upon which to rest the sill. For buildings of a See also:superior kind a See also:combination of the braced and balloon frames is sometimes adopted. The sides of frame buildings are covered with siding, which is fastened to a sheathing of rough boards nailed to the studs. The siding may consist of matched boards placed diagonally, or' of clapboards or See also:weather boards—which are thin boards thicker at one edge than the other, and arranged horizontally with the thick edge downwards and overlapping the thin edge of the board below. Shingles or wooden tiles are also employed. Additional information and CommentsThere are no comments yet for this article.
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