A chamfer on each joint or bed, forming a V joint between the two beds, is often substituted for the plain rebate, as fig. 240; or again, the joint may be moulded, as fig. 241.
Birdsmouth and squint quoins refer to the irregular internal and external angles, as explained for bricks.
Scuntion quoins are the rough squared angle quoins used in rubble walling at the plumbings of internal openings.
Copings to walls, otherwise called water tailings, ate explained in Chapter IV (Damp And Its Prevention. Danger Of Damp). (figs. 193, 194, 195, 196, and 197) under Brickwork; the same remarks and illustrations applying to stone copings, which, it must be noticed, are much extensively used; and especially up the sloping tops of gable-walls, as X, fig. 242.
The bottom stone, A, with the coping worked on it as shown, is called a springer; that at the top, B, the apex, being similar to a ridge; and intermediate stones, C, whereof the object is to give the coping a firmer hold on the wall, are called kneelers or knee-stones. Fig. 243 is a section of the coping described as moulded, throated, and feather-edged, because it is weathered from a thick edge to a thinner one.
It is almost needless to remark that most of the above dressings are worked with labours similar to those explained in Chapter V (Building Stones And Stone Walling. Stone As A Building Material).; so that a special name given to a particular dressing is intended to convey to the student the manner of the labour that it has had upon it, as previously explained with regard to quoins.
Good masonry often requires that the joints be secured together by special means, so that the various members may be united into one mass, in length as well as in height. Longitudinally they are bound together by means of cramps, which are strips of galvanised iron or copper, turned down at each end into each of two adjoining stones and run in with molten lead, or "leaded in," as figs. 244 and 245.
Section. Fig 246.
Lead dovetails or plugs consist of a wedge-shaped mortise cut into each stone at this joint, as fig. 246, and run in with lead, which binds the two stones together. Sometimes this dovetail is mortised out below the bed of the stones at the joints, as fig. 247, the lead being poured in through the hole from the top or bed-joint.
Rebated joints are suitable for copings to gables and similar work, a rebate being sunk out of each stone alternately, as fig. 248, one stone lapping, as it were, into the rebate of the other.
The stones are secured vertically by means of dowels, either of pebbles, slate, or copper, about 1 inch square, and of different lengths, according to circumstances; one half or part being let into the top bed of the bottom stone, the other half going into a similar mortise on the bottom bed of the upper stone, as fig. 249. They are run in with cement to render them firm and to fix the dowels securely in the mortises. This joint is very suitable, and much used for securing mullions to sills, heads, and transoms at the stoolings.
Joggle joints are used to connect stones in different positions, this form of joint being suitable for ashlar, as well as for cornices, strings, landings, etc. The simplest form of it is to cut a V groove roughly on the joints of adjoining stones, as fig. 250, and, when they are bedded up to each other, to run into the hole liquid cement, which sets hard, and connects the stones together. Landings are joggle jointed, as in fig. 251, the tongue, as it may be called, on the one stone being let into a groove of similar section on the other.
Tabled joints are little used, but they are formed by letting a wide projection of one stone into a sinking in another.
Cornices and other large projections often have their joints saddled, which is done to throw the water off the joints, being carried out by leaving a projection or stop on the weathering at the joint at each end of each stone, as fig. 252.
Dressings for stone stairs have the same names and terms (as far as they go) applied to them, as will be explained under "wooden stairs," Chapter XIX (Wooden Stairs. Stairs And Staircases)., to which the student is referred. But stone stairs, unlike wood stairs, are of simple construction, though they may be of the same various kinds.
Stone steps consist of solid blocks of stone, of various sections - square, as fig- 253 and spandril, as fig. 254 - each being plain or moulded, according to taste. They are supported by being built into the walls from 4 1/2 to 9 inches, according to the width of the stair and the projection of the steps, or the distance to which they hang out. Some kinds, however, are built with both ends into the walls, as in straight stairs similar to fig. 798 (Chapter XIX (Wooden Stairs. Stairs And Staircases).).
Dog-legged stairs, as fig. 804 (Chapter XIX (Wooden Stairs. Stairs And Staircases).), whether with or without winders, and open, or geometrical stairs, as explained by figs. 812, 815 (Chapter XIX.), are, of course, essentially hanging stairs, tailed into the enclosing staircase walls from 4 1/2 to 12 inches, as required, the landings also being treated in the same manner. Each step is supposed to assist in supporting those above it, and for that purpose, and for better workmanship, they are jointed, as figs. 355, 256 and 257; the latter being a section of a moulded step, of which the end view, with the moulding returned, is shown on fig. 358.
The soffits are generally left plain, with a nibbed face.
Circular stairs, or turret steps, are built up of steps of a form illustrated by fig. 259, the wide ends being built into the wall and the rounded ends laid one upon the other, forming a sort of newel in the centre, from which all the risers radiate, appearing on plan as fig. 260.
The handrailing of stone stairs is generally supported by wrought-iron bar balusters, about 1 inch square, mortised and leaded into the tread of each step, though sometimes they are secured by burning liquid sulphur, which sets very hard on cooling.
The newels may be of wrought or cast-iron, according to the amount and class of ornament required, mortised and leaded into the steps (like the balusters). The whole may be filled in with scroll-work or other ornament, to make it showy and light, according to taste. The tops of the balusters and handrail are connected by a thin wrought-iron core, which is sunk into the underside of the handrail, and secured by screws, making the staircase and its requisite accessories one connected mass.