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PLAN FIG
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See also:PLAN FIG . 7.
Blocking Course, a heavy course of See also: A deep drip should always be worked in the upper members of a cornice to prevent the rain trickling down and disfiguring the face of the moulding and the wall below (fig. 8). See also:Corbel, a stone built into a wall and projecting to form a See also:cantilever, supporting a load beyond the face of the wall. It is frequently richly ornamented by See also:carving (fig. 7). Skew Corbel, a stone placed at the See also:base of the sloping side of a gable wall to resist any sliding tendency of the sloping coping. Stones placed for a similar purpose at intervals along the sloping side, tailing into the wall, are termed " kneelers " and have the See also:section of the coping worked upon them (fig. 7). Corbel Table, a See also:line of small corbels placed at See also:short distances apart supporting a parapet or See also:arcade. This forms an ornamental feature which was much employed in See also:early See also:Gothic times. It probably originates from the machicolations of See also:ancient fortresses. Dressings, the finished stones of window and See also:door jambs and See also:quoins. For example, a " See also:brick See also:building with stone dressings " would have brick walls with stone door and window jambs, heads and sills, and perhaps also stone quoins (fig. 7). See also:Diaper, a square See also:pattern formed on the face of the stonework by means of stones of different See also:colours and varieties or by patterns carved on the surface (fig. 7). See also:Finial, a See also:finishing See also:ornament applied usually to a gable end '(fig. 7). Gablet, small gable-shaped carved panels frequently used in Gothic stonework for See also:apex stones, and in See also:spires, &c. See also:Gargoyle, a detail, not often met with in See also:modern See also:work, which consists of a See also:waterspout projecting so as to throw the rain-water from the gutters clear of the walls. In early work it was often carved into See also:grotesque shapes of See also:animal and other forms. Galleting.—The joints of See also:rubble are sometimes enriched by having small pebbles or chips of See also:flint pressed into the See also:mortar whilst See also:green. The joints are then said to be " galleted." See also:Jamb.—Window and door jambs should always be of dressed stone, both on See also:account of the extra strength thus gained and in See also:order to give a finish to the work. The stones are laid alternately as stretchers and headers; the former are called outbands, the latter inbands (fig. 7).
See also:Label Moulding, a projecting course of stone running See also:round an See also:arch. When not very large it is sometimes cut on the voussoirs, but is usually made a See also:separate course of stone. Often, and especially in the See also:case of door openings, a small sinking is worked on the top surface of the moulding to form a See also:gutter which leads to the sides any water that trickles down the face of the wall.
Lacing Stone.—This is placed as a See also:voussoir in brick See also:arches of wide span, and serves to See also:bond or See also:lace several courses together (see
See also:BRICKWORK).
Lacing Course, a course of dressed stone, bricks or tiles, run at intervals in a wall of rubble or flint See also:masonry to impart strength and tie the whole together (fig. 7).
Long and Short Work, a typical Saxon method of arranging quoin stones, See also:flat slabs and long narrow See also:vertical stones being placed alternately. Earls See also:Barton See also: The gutter lies behind, and waterways are formed through the parapet wall for the See also:escape of the rain-water. See also:Plinth, a projecting base to a wall serving to give an See also:appearance of stability to the work. Quoin, the See also:angle at the junction of two walls. Quoins are often executed in dressed stone (Fig. 7). Rag-See also:bolt, the end of an See also:iron bolt when required to be let inta stone is roughed or ragged. A dovetailed See also:mortise is prepared in the stone and the ragged end of the bolt placed in this, and the mortise filled in with molten See also:lead or See also:sand and See also:sulphur (fig. 9). See also:Sill, the stone which forms a finish to the wall at the bottom of an opening. Sills should always be weathered, slightly in the case of door sills, more sharply for windows, and throated on the under side to throw off the wet. The weathering is not carried through the whole length of the sill, but a See also:stool is See also:left on at each end to form a square end for building in (fig. 7). See also:String Courses, See also:horizontal bands of stone, either projecting beyond or flush with the face of the wall and often moulded or carved. They are frequently continuations of the sills or See also:head lines of windows (See also:figs. 5 and 7). Scontion.—In a thick wall the dressed stones forming the inside angles of the jamb of a window or door opening are termed scontions. Spalls, small pieces chipped off whilst working a stone. Templates, slabs of hard stone set in a wall to take the ends of a See also:beam or girder so as to distribute the load over a larger See also:area of the wall. Tympanum, the triangular filling of masonry in a See also:pediment between the cornices, or between the horizontal head of a window or door and the under-side of the relieving arch above it. It is often panelled or enriched with carved ornament (fig. 7). Throat, a groove worked on the under-side of projecting See also:external members to intercept rain-water and cause it to drop off the member clear of the work beneath (fig. 8). Weathering.—The surface of an exposed stone is weathered when it is worked to a slope so as to throw off the water. Cornices, copings, sills and string courses should all be so weathered. Voussoirs, the See also:wedge-shaped blocks of which an arch is built up. Methods of finishing Face of Stones.—The self face or See also:quarry face is the natural surface formed when the stone is detached from the See also:mass in the quarry or when a stone is split. Saw face, the surface formed by sawing. See also:Hammer-dressed, See also:Rock faced, or See also:Pitch-faced.—This face is used for See also:ashlar-work, usually with a See also:chisel-draughted margin around each block. It gives a very massive and solid appearance to the See also:lower storeys of masonry buildings, and is formed with little labour, and is therefore the cheapest face to adopt for ashlar-work (fig. 7). Broached and Pointed Work. This face is also generally used with a chisel-draughted margin. The stone as left from the See also:scabbling hammer at the quarry has its rocky face worked down to an approximate level by the point. In broached work the grooves made by the See also:tool are continuous, often running obliquely across the face of the block. In pointed work the lines are not continuous; the surface is rough or See also:fine pointed according as the point is used over every inch or See also:half-inch of the stone. The point is used more upon hard stones than soft ones (fig. 7). Tooth-chiselled Work.—The cheapest method of dressing soft stones is by the toothed chisel which gives a surface very much like the pointed work of hard stones. Droved Work.—This surface is obtained with a chisel about two and a half inches wide, no See also:attempt being made to keep the cuts in continuous lines. Tooled Work is somewhat similar to droved work and is done with a flat chisel, the edge of which is about four inches wide, care being taken to make the cuts in continuous lines across the width of the stone. Combed or Dragged Work.—For soft stones the See also:steel See also:comb or See also:drag is often employed to remove all irregularities from the face and thus form a fine surface. These tools are specially useful for moulded work, as they are formed to See also:fit a variety of curves. Rubbed Work.—For this finish the surface of the stone is previously brought with the chisel to a level and approximately smooth face, and then the surface is rubbed until it is quite smooth with a piece of grit stone aided by fine sand and water as a lubricant. See also:Marbles are polished by being rubbed with gritstone, then with See also:pumice, and lastly with See also:emery See also:powder. Besides these, the most usual methods of finishing the faces of stonework, there are several kinds of surface formed with hammers or axes of various descriptions. These types of hammers are more used on the See also:continent of See also:Europe and in See also:America perhaps than in See also:England, but they deserve See also:notice here. See also:Pan. See also:Saddle
tl
r flocking CC~ourse.
Saddle.
Drip
Secii .
leant. n
_Rags See also:BoW
The toothed See also:axe has its edges divided into See also:teeth, fine or coarse according to the work to be done. It is used to reduce the face of limestones and sandstones to a See also:condition ready for the chisel. The See also:bush hammer has a heavy square-shaped See also:double-faced head, upon which are cut projecting pyramidal points. It is used to form a surface full of little holes, and with it the face of sand and limestones may be brought to a somewhat ornamental finish. The patent hammer is used on See also:granite and other hard rocks, which have been first dressed to a See also:medium surface with the point. The fineness of the result is determined by the number of See also:blades in the hammer, and the work is said to be " six," " eight " or " ten-cut " work according to the number of blades inserted or bolted in the hammer head. The See also:crandall has an iron handle slotted at one end with a hole iSin. wide and 3 in. long. In this slot are fixed by a See also: It gives a fine pebbly sparkling appearance. There are several methods of finishing stone which involve a See also:great See also:deal of labour and are therefore expensive to work, but which result in imparting a very stiff and unnatural appearance to the masonry. Vermiculated Work.—T his is formed by carving a number of See also:curling See also:worm-like lines over the face of the block, sinking in between the See also:worms to a See also:depth of a See also:fourth of an inch. The surface of the strings is worked smooth, and the sinkings are pock-marked with a pointed tool (fig. 7). Furrowed Work.—In this face the stone is cut with a chisel into a number of small parallel grooves or furrows (fig. 7). Reticulated Face is a finish somewhat similar to vermiculated work, but the divisions are more nearly squares. Face Joints of Ashlar.—The face joints of ashlar stonework are often sunk or rebated to form what are termed rusticated joints; sometimes the angles of each block are moulded or chamfered to give See also:relief to the surface or to show a massive effect (fig. 7). Joints in Stonework.—The joints between one block of stone and another are formed in many ways by cramps, dowels and joggles of various descriptions. The stones of copings, cornices and See also:works of a similar nature, are often tied together with See also:metal cramps to check any tendency for the Cramps. stones to separate under the force of the See also:wind (figs: to and I I). Cramps are made of iron (See also:plain or galvanized), See also:copper or See also:gun-metal, of varying sections and lengths to suit the work. A typical See also:cramp would be about 9 in. long, 1 or 11 in. wide, and from } to It in. thick, and turned down about t } in. at each end. A See also:dove-tailed mortise is formed at a suitable point in each of the stones to be joined and connected by a See also:chase. The cramp is placed in this channel with its turned-down ends in the mortises, and it is then fixed with molten lead, sulphur and sand, or See also:Portland See also:cement. Lead shrinks on cooling, and if used at all should be well caulked when See also:cold. Double dovetailed See also:slate cramps bedded in Portland cement are occasionally used (fig. II). Dowels are used for connecting stones where the use of cramps would be impracticable, as in the joints of window mullions, the shafts Dowels. of small columns, and in similar works (figs. 7, 8 and 20). Dowels for bed and side joints may be used. They are of slate, metal, or sometimes of hard' ard See also:wood. There are many ways of making a joggle joint. The joggle may be worked on one of the stones so Joggles. as to fit into a. groove in the adjoining stone, or grooves may be cut in both the stones and an See also:independent joggle of slate, pebbles, or Portland cement fitted, the joggle being really a See also:kind of dowel. The pebble joggle joint is formed with the aid of pebbles as small dowels fitted into mortises in the jointing faces of two stones and set with See also:Port-See also:land cement; but joggles of slate have generally taken the See also:place of pebbles. Portland cement joggles are formed by pouring cement grout into a vertical or oblique mortise formed by cutting a groove in each of the joining surfaces of the stones. What is known as a he- and-she joggle, worked on the edges of the stones themselves, is shown in fig. 13. Plugs or dowels of lead are formed by pouring molten lead through a channel into dovetailed mortises in each stone (figs. 14 and 15). When cold the metal is caulked to compress it tightly into the holes. The saddle joint is used for cornices, and is formed when 'a portion of the stone next the joint is left raised so as to See also:guide rain-water away from the joint (fig. 8). Two forms of, rebated joints for stone copings and See also:roofs are See also:common. In one form (shown in fig. 7) the stones forming the coping are thicker at their lower and rebated edge than at the top plain edge, giving a stepped surface. The other form has a level surface and the stone is of the same thickness throughout and worked to a See also:rebate on top and bottom edges. In laying stone roofs the joints are usually lapped over with FIG. 15. an upper slab of stone. Joints in Spires.—Four forms of jointing for the battering stone-work of spires are shown in fig. 16. A is a plain horizontal joint. B is a similar joint formed at right angles to the face of the work. This is the most economical form of joint, the stone being cut with its sides square with each other; but if the mortar in the joint decay moisture is allowed to penetrate. With these t- .1 Lead Jog g'e forms dowelling is frequently necessary for greater stability. The ;Dints C and p are more elaborate and much more expensive on account of the extra labour involved in working and fitting. Where a concentrated weight is carried by piers or columns the bed joints are in many cases formed with-out the use of mortar, a thin See also:sheet of milled lead being placed between the blocks of stone to fill up any slight inequalities. Moulded Work. The working of
See also:mouldings in stone is an important
part of the See also:mason's See also:craft, and forms
a costly See also:item in the erection of a stone
structure. Much skill and care is re-
quired to retain the arrises See also:sharp and
the curved members of accurate and
proportionate outline. As in the case
of wood mouldings, machinery now
plays an important part in the pre-
paration of See also:store moulded work. The
See also:process of working a stone by See also:hand
labour is as follows: The See also:profile of
the moulding is marked on to a See also:zinc
template on opposite ends of the
stone to be worked; a short portion, an inch or two in length
termed a " See also:draught," is at each end worked to the required section.
The remaining portion is then proceeded with, the craftsman See also:con-
tinually checking the accuracy of his work with a straight-edge and
zinc templates. A stone to be moulded by machinery is fixed to a
moving table placed under a shaped tool which is fixed in an immov-
able portion of the See also:machine, and is so adjusted as to cut or chip off a small layer of stone. Each See also:time the stone passes under the cutter it is automatically moved a trifle nearer, and thus it gradually reduces the stone until
the required shape is attained.
Iron in Stonework.—The use of iron dowels or cramps in stonework, unless entirely and permanently protected from oxidation is attended by the gravest risks; for upon the expansion of the iron by rusting the stone may split, and perhaps bring about a more or less serious failure in that portion of the building. A case in point is that of the church of St See also:Mary-le-Strand, See also:London, where the ashlar facing was secured to the backing with iron cramps; these were inefficiently protected from See also:damp, with
the, result that many of the blocks have been split in consequence of rusting. See also: 16. Additional information and CommentsThere are no comments yet for this article.
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