How Does a Window Crank Work?

Crank windows are made for easy opening, particularly when a window is located in a hard-to-reach place like over a kitchen sink where leverage needed to lift the window open may be difficult. Some casement windows have a crank mechanism that opens the window from the side by cranking in a clockwise rotation. These mechanisms are referred to as window operators, as they control the sash on casement windows. A window bar and linkage arm support the window glass, which is opened or closed using a small handheld crank. Turning the crank handle causes the sash to open or close.

Operate by placing the crank handle on the crank stud with the handle pointing upward in the 12 o'clock position. Manually rotate the crank handle clockwise (to the right) until the window opens to the desired position. Rotate crank handle in a counterclockwise direction or to the left to close the window. Keep in mind that trying to force a crank window closed or continuing to crank the window after you close it can strip the spline inside the handle. Many styles of window crank handles are designed to fold out of the way when not in use.

Crank windows need to be regularly maintained so that they open and close smoothly. Since the arm hinge and crank are exposed to considerable wear and tear over time, you want to keep window crank operators and handles in good repair so that you can prevent problems. You don't want handles that fall off the windows, or arm hinges that won't extend all the way. The good news is that worn window cranks are usually easy to repair or replace. Periodically inspect both the crank mechanism and crank handle for wear. If gears look worn, you should probably replace the opener crank. The gears may be stripped if the crank handle simple spins when you turn it. Even if the crank mechanism doesn't need to be replaced, take the time to lubricate the hinges. Inspect the track to be sure that it isn't bent. Also, check to see if you have to adjust the roller.

Begin by opening the window until the roller at the end of the extension that opens the window is aligned with the slot in the window track. The next step is to pull the extension arm down and out of the track. Use a screwdriver to remove the crank assembly. Take out the mounting screws and lift off the crank. Once you remove the assembly, clean the track using a small brush like a toothbrush and then vacuum to remove any loose dirt. If the window track is wood, lubricate the track by rubbing a wax candle along the track and roller. If you need to replace the crank, line up the new mechanism with the old holes. Whether or not you replace the entire crank operator, replace any rusted or bent screws before reattaching the crank arm.