THE smooth opening and closing of the ordinary sliding sash is controlled by concealed balancing weights which are attached by cords to the left and the right top sides of the sash. These cords run over pulleys in the top of the frame, and the weight on the end of each cord rises and falls in the space provided in the interior of the frame. The balancing weights secured to the cords for the top sash are slightly heavier than the total weight of the sash. This ensures that the top sash will not tend to slide open from the closed position. The balancing weights of the bottom sash for a similar reason should be about equal to the total weight of the bottom sash. When a sash cord breaks, after long use, its metal weight temporarily ceases to be of use in the operation of raising or lowering the sash, until the broken cord has been replaced by a sound one. The broken cord can generally be detected because part of it hangs loosely outwards on its pulley, or the cord may cause the sash to jam in the frame. Access to the weight is provided by a pocket in the side of the framework, sealed by a strip of wood which is removable.
Renewing a Sash Cord
To replace a broken cord with a new one (sash cord is generally available at ironmongery or builders’ stores), remove the length of beading, which runs from top to bottom of the frame, on the side where the break has occurred. To avoid damage to paint and wood, care- fully lever out the beading, using a screwdriver or wood chisel inserted close up to each of the securing nails; it will then come away without trouble if bulged out at the centre. With the beading removed, the lower sash (if that is the affected one) is raised just far enough to clear the horizontal beading at the bottom and swung to one side; its only attachment to the window frame then being the sound cord. Support the sash on a box or chair. The pocket in the frame may be located by looking for the horizontal cracks marking the top and the bottom of the strip. If it is not apparent, because of a covering of paint, a light tap or two with the hammer will cause the joint to show. The strip is then levered out with the screwdriver inserted at the bottom, and the weight lifted out of the pocket.
The two broken pieces of cord have now to be removed: one from the weight, the other from the top of the window which has been swung clear. The latter piece is attached by clout nails and also, in some instances, by staples; these should be extracted by pliers or pincers. The piece of new sash-cord must match the combined length of these two pieces exactly, and when the new piece has been cut to that length, one end is to be passed over the pulley for attachment to the weight. Tie a piece of string to the cord-end, and to the free end of the string attach a thin piece of lead about 3 in. long by½ in. diameter. Pass this over the pulley and allow the weight to carry the string down and inside the channel to the pocket opening. Draw down the cord, detach the string and be careful not to draw the top end out through the pulley. The cord is then pulled gently through the pocket opening, just far enough to enable it to be tied to the metal balancing weight in the same way as the old one was fastened. Do not waste any of the cord in so doing. The top or free end can then be nailed in the window sash groove which the old piece had occupied. It will be necessary to lift the sash close to the frame while the nails and staples are driven through the new cord. The repair thus completed, the cover rs replaced over the pocket opening, the window goes back to its original place, and the beading, which was removed at the beginning of the operation, is nailed back in position.
When the occasion arises to change one cord, examine the other three for signs of wear and renew these at the same time if necessary.
To replace a broken pane of glass the simple requirements are a new pane, some putty, a putty-knife or an old stiff-bladed of which has broken. It will be necessary to extract the lower sash, first by removing the beading on the same side of the frame as the broken top cord, then by raising the lower window an inch or so (to clear the bottom beading) and pulling it right out of the frame; it is then released so that it hangs, inside the room, by its two cords. Separating top and bottom sashes, at each side, is a long parting bead running from top to bottom, and this has next to be pulled or levered out of the groove that holds it. The strip is usually not nailed or otherwise fastened, but if paint prevents it being shifted it will need to be prised out. That allows the top window sash to be swung down into the room, exposing the groove at the top of the sash to which the new cord is to be attached.Thereplace-ment is carried out in the same manner as when dealing with a bottom window. When this is completed, the top sash is replaced in position, the long upright parting-bead next, then the ‘lid’ of the pocket goes back, and finally the lower window. The whole is made secure by nailing the side beading on the frame. Knife, an old wood chisel or similar tool, a hammer and some glazing brads or short nails. If the glass is to be cut at home a glass-cutter will be needed. Exact measurement of the new pane is most important; it should be ½ in. less in length and½ in. less in width than the space it is to fill. And that space can be measured accurately only after the broken glass and all the old putty have been removed, as explained in a later paragraph.
Whatever broken glass can be pulled away by hand is first dealt with; the importance of guarding the hands against cuts need not be stressed. The broken glass that refuses to budge will come away as the putty is chipped out of the frame. Chipping, with a stiff knife, or for preference an old wood chisel, must be done without injury to the surrounding wood. If the tool has to be helped with a tap or two from the hammer the possibility of an adjacent pane being cracked by the vibration must be carefully considered. As the putty is removed, a few brads will be encountered; draw these out with pliers. Next, the thin layer of putty on which the glass was bedded is chipped out, the corners receiving careful attention.
The piece of glass which is to be cut (minus the ½ in. on length and width previously mentioned) is placed on a flat and speckless table or bench, overlaid with an old blanket to protect the glass, and the first measurement is marked off with a ruler against the edge of a tee-square lodged against one straight edge. The cutter, gliding against the side of the tee-square leg, is drawn firmly but lightly from the farther edge of the glass towards the operator. If all goes well the cutting is accompanied by a sharp, even sound; if there is a grating noise the glass is simply being roughly scratched, in which case the glass should be turned over and another attempt made on the reverse side.
A clean and continuous cut having been made, the glass is moved to the edge of the bench or table, the cut being immediately above that edge. Downward, quick pressure of the hand should cause the glass to part cleanly; and here it is as well to wrap the hand in a thick duster, in case of an accident. If the glass does not respond to the pressure, tapping on the underside, along the parting line of the glass, with a knife-blade or something similar, should prove effective. Where the surplus is of only narrow width it may be more easily persuaded to come away by levering it carefully with a pair of pliers or pincers.
The new glass reduced to correct dimensions, it is bedded on a thin layer of putty pressed into the frame with the thumb, a couple of brads then being lightly hammered into each side of the frame to hold the glass down to its bed. The outside putty is then applied, first with the thumb, then smoothed to an even slope with the blade, the latter being drawn from one end to the other. A certain amount of the bedding-putty will be squeezed out, on the room side of the glass, and this is cleaned off with the knife. A coat of paint applied to the putty completes the job.
This reglazing has to be done from the outside, and may involve the use of a pair of steps, or a ladder. There is, of course, the ‘ simple expedient of sitting on the window sill. However it is safer to take the window completely out of the frame and shift it to a table or bench where the work can be done in comfort. To do this, the beading is removed from one side of the framework, the sash cord then being pulled until the weight at its end has been hoisted as far as the pulley, and there the cord is pinned, with a large-headed nail driven through it into the woodwork immediately below the pulley so that it cannot slip back. The sash-cord on the other side is dealt with in the same way. The ends of the cords that are nailed to the top of the left and right sides of the window have then to be freed, thus enabling the window to be lifted right out. Reversal of this procedure, after completion of the reglazing, sees the window in action again. In dealing with a top sash it will be necessary to take out the vertical dividing-strip, as already detailed.