This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
In all the range of house hardware, there is none so unsatisfactory as that used in connection with window-sashes. This is not altogether the fault of the hardware, as the customs regulating the manufacture of the sashes themselves make them the most flimsy part of house construction. The glass is wide, and the meeting rails narrow. Sooner or later someone tries to force up the lower sash when "stuck," by pushing violently on its top rail, or tries to pull down the top sash by pulling on its bottom rail; these operations pull the rails away from the glass, and if, when "fitted," there was not considerable play, the sashes never come together again. Any sash-lock adapted to such a position must necessarily be far from exact in its working. All work perfectly in the model; few work at all on the real sash. Therefore, in selecting this fixture, it is wise to pick out the strongest which will allow for variation in the rails, and, before purchasing, to visit some house in which they have them installed, in order to see how they work. The material of which sash-locks are made makes little difference, as they are generally out of sight. Little attention need be paid to representations that certain kinds can be opened by means of a thin blade inserted between the sashes from the oustide; for, after one has seen the difficulty of working them from the inside by the usual means, he will never be troubled by the thought of anyone working them from the outside with a putty-knife.
There are certain kinds which throw up the arm against the glass of the upper sash when unlocked. This kind should not be used, as they at once give notice to anyone outside, if the window has been left unlocked.
Window pulls or handles on the lower sash are always very difficult things to get a "purchase" on with the ends of one's fingers when the sash "sticks;" and while the socket in the top sash with a pole and hook to move it, is a trifle the most exasperating of any part of window hardware, manufacturers have as yet failed to remedy the trouble.
There are on the market quite a large number of complicated devices for operating sashes, either swinging them into the room or sliding them up and down; but in practice the old trouble of flimsy sash construction makes such devices of no more value than those of the old form. It is doubtful whether any remedy will be found until custom requires the use of smaller glass, of sash bars to stiffen the sash, and of better carpentry work in fitting, and requires owners to keep all parts of sashes and frames thoroughly oiled to prevent the constant absorption of dampness, thus preventing swelling and shrinking with their concomitant effects of sticking and rattling.
When sashes are hung at the side - as is frequently the case - they should swing outward; if they swing inward it is difficult to keep out storm water. For holding them at any required angle, bars are made with clamp screws (Fig. 44). These work very satisfactorily; but, unless great care is exercised to leave the sash always firmly clamped, sudden wind may wreck the sash and glass, leaving no protection from the storm. As a general thing, accordingly, it is better to retain the old sliding type of window, especially since, with swinging windows, the use of outside blinds is impossible.
Fig. 44. Sash Fastener.
The sash-pulley (Fig. 45) is out of sight, and often almost anything in the way of material and make is considered good enough. This particular piece of hardware, however, receives so much wear, and is capable of wearing out so much good window-cord, that, if the future is to be reckoned with, care should be taken in its selection. First of all, the wheel should be as large as possible, as the constant crimping of the sash-cord over a wheel of short radius rapidly destroys the fibre, so that after giving great annoyance for a time by becoming caught in the wheel, the cord finally breaks and lets the weight drop to the bottom of the pocket.
For plate-glass windows or wide, heavy sash, chains are generally employed. They are composed of links which follow the curve of the wheel (Fig. 46), and are not easily worn out. The groove in the wheel should be square to conform to the lines of the chain, and not as for cord (see Fig. 47).
Fig. 45. Sash Pulley.
Fig. 46. Sash Chains.
The pocket in which the window weight runs, should never be less than two inches in depth (crosswise), nor the pulley-style less than ⅞ of an inch thick. Thus it will be evident that to allow the weight to hang in the middle of the box, the wheel of the pulley must be not less than two inches in diameter on its running face; that is, the diameter of the wheel should always be equal to the thickness of the pulley-style plus one-half the depth of the box (see Fig. 48). The diameter here indicated is considerably larger than that of the pulley wheel used in common practice. If, however, a smaller wheel is used, not only is the cord rapidly destroyed by the constant crimping, but the weight "drags" on the back of the pulley-style, making the operation of the sash difficult and noisy.
Pulley wheels are generally measured by manufacturers and dealers, to the outside of the flanges, so that a wheel two inches on the running face is often styled a 2½-inch wheel. The money invested in such a wheel is gained many times over in saving the annoyance and expense of broken sash-cord.
Fig. 47. Sections of Sash Pulley Rims - A, for Chain: B, for Cord.
If the pulley is steel-bushed and has roller bearings, it will be better in the long run, and these items add little to the expense. The running face of the wheel should be smooth; and all parts may be of iron, without detriment to the appearance or the usefulness of the fixture. A plain brass or bronze face and wheel are to be preferred, however, if the small additional expense is not a bar.
The pulleys usually put in stock frames are 1½-inch iron pulleys costing about 50 cents a dozen; and 10 cents a dozen is usually added for each additional quarter-inch in the diameter of the wheel, though the mill man will often want a little extra for making the frame "special" in case the larger wheel is used. The brass wheel with roller bearings and brass face will cost about three times the above price - or, possibly, 50 cents extra for each window.
There are on the market very useful pulleys over which the sash-cord can be carried to boxes several feet away (Fig. 49). Pulleys of this type can be used where the mullions between windows are too small to carry the weights. These pulleys dispense with the necessity for lead weights, which are expensive and are usually crowded into boxes so small that they work unsatisfactorily. By the use of combinations of these pulleys, the cord can be carried an indefinite distance to a box capable of receiving a large iron weight, and the width of the mullion can be reduced to the minimum thick-
Fig. 48. Section of Pulley and Pulley-Style; Showing also Sash and Weight.
Sash-cord is a very important item, and braided cotton cord is probably the cheapest in the long run. It is better to get a small rather than a large size. The wearing of the cord is due to the fact that in passing over the pulley the inside or the part against the wheel is compressed or crimped, while the opposite side is stretched, thus producing a constant wear and strain of the fibre of the cord, which finally breaks it down. It will be evident that this disintegrating action will increase with the larger diameter of the cord. A cord just large enough to hold the weight safely, is the best. A simple test is to suspend four of the heaviest weights to be used, by one cord; if it will hold them, it is sufficient size to carry the one weight.
Fig. 49. Pulley Arrangement for Carrying Sash Cord to Distant Boxes.
Taken as a whole, the window - with its lock which rarely works, its exasperating pulls, and its sash-cord broken when most needed - is one of the oldest, and still one of the greatest, of modern inconveniences. Undoubtedly the first step necessary to make the window more satisfactory, it to make the sash narrower and cut the glass smaller, with substantial muntins, so that the sash will be firm. This, with a little better workmanship on the frames, will, with present appliances, make a very satisfactory window.