CASEMENT windows that swing open and close like a door and have hinges along one side will usually work for many years without trouble. But in time most will need some periodic maintenance to keep them operating smoothly. As they age, some no longer close as snugly as they should, allowing cold drafts and even water to enter when a storm strikes. Fortunately, most such problems can be corrected with minor repairs or adjustments that are not difficult for the homeowner. Most casement windows are opened and closed by means of a crank mechanism that is mounted against the frame on the inside. Turning the handle on this causes a control arm to move, pushing the window open or pulling it closed, depending on which direction the handle is turned. The enclosed crank mechanism consists of a series of gears inside a metal housing. The gears are usually packed in grease to make turning easy, but it helps to apply a few drops of oil around the base of the handle, as shown in the drawing.
To keep things working smoothly, the handle on each window crank mechanism should be lightly oiled in this manner about once a year. Try to drip the oil into the joint between the end of the handle and the housing into which it fits. Or you can remove the handle, usually held on by a setscrew, then work a little oil onto the end of the handle shaft. If the window seems hard to open or close, one of the first things to check is the control arm and the track in which it slides. The control arm is the lever or arm that connects the crank mechanism on the inside with the swinging sash. First, inspect the track in which the end of the control arm slides. This track may be along the inside face of the sash near the bottom, or it may be along the bottom edge of the sash, where you cannot easily see it. Either way, the end of the control arm should slide easily along in this track to push the window open, or pull it closed, with a minimum of effort. If it doesn't slide easily, or seems to catch and jam periodically, use a wire brush to carefully clean out the insides of the track, making certain you remove all dirt, rust or caked-on paint.
Then lubricate the track by smearing on a light coat of waterproof grease or petroleum jelly to help the sliding action. In some cases it is not the track that is causing the problem, it is the crank or handle mechanism. The problem may arise because there is not enough grease inside to keep the gears working smoothly, or the grease may be old, dried out and caked with dirt. In each instance, a thorough cleaning and regreasing is required. The crank mechanism is usually held in place with two screws, one on each side of the housing, as shown. After removing the screws, pull the housing away from the frame of the window. The control arm will remain attached, but it should slide inward easily through the slot in which it fits after you disengage the other end from the track on the sash. You should be able to do this by sliding the far end out of one end of the track on the sash, as previously described. But don't force or pry it out. It should slide out easily. When the mechanism has been removed, turn it over and you will usually find a single large screw that holds all the gears in place on the inside.
Loosen this so you can remove the gears, then flush them out thoroughly with kerosene or a similar solvent to loosen and remove the old grease and dirt. Do the same with the other parts on the inside, including the inside of the housing itself. Then coat everything with a film of light grease and reassemble the mechanism. If, while you have the handle mechanism apart, you find that the gears are chipped, broken or bent, chances are you will have to buy a whole new unit. Check with your local lumberyard or building materials dealer to see if they have one that will match, or, if not, can order one for you. If they can't, they can often direct you to a source of supply. Another problem that can cause difficulty in opening and closing windows is loose hinges or mounting hardware. Loose hinges will allow a sash to sag out of alignment, making it difficult to open or close and impossible to close tightly. That's why it is important to check all screws and bolts regularly, especially hinge screws.
Tighten those that seem loose and replace those that are badly rusted. Don't forget the fasteners that hold the locking levers or locking handles in place - these are the handles that pull the window shut and secure them when fully closed. A frequent complaint with many older casements is that they do not close tightly and thus allow a lot of cold drafts to enter in winter and hot air to enter in summer. On many windows the sash is locked shut and drawn up tight against the frame of the window with a hook-type lever, or handle, similar to the one shown in the drawing. When this handle is pressed down on the inside, its eccentrically shaped hooked end catches a slot in the sash frame and pulls it tightly shut. If this handle does not pull the sash as tight as it should, try bending the lip of the strike plate that is mounted on the outside edge of the sash frame. If this doesn't do the trick, you can often help to pull the sash in more tightly by removing the handle and inserting a thin metal or plastic shim (a spacer) under its mounting plate as illustrated here.
This shim will have the effect of slightly shortening the outer ''hook'' that locks the sash shut, and thus will cause it to pull the window more tightly closed than before. On metal window frames, another common cause of poor closing and sealing is a bent section on the frame, or a section of the frame that has accumulated a thick layer of rust. Either of these will act as a ''bump'' that keeps the window from closing all the way. Bent sections of a metal frame can be straightened by gripping firmly with large locking pliers or wrench, then bending the metal to straighten it. Another way to eliminate drafts and energy leaks is to install plastic or foam-type weatherstripping around all sides of each sash. Hardware stores and home centers carry a variety of long-lasting types that work well on casement windows. In addition, you should install storm windows on all your windows in the winter. On casement windows, this is usually easier to do on the inside than on the outside. Questions about home repair should be addressed to Bernard Gladstone, The New York Times, 229 West 43d Street, New York, N.Y. 10036.