If you have a casement window and after unlatching the lock the handle of the crank just spins without opening the window you have a little problem. You may be able to repair casement window cranks, but it all depends on how big the problem is. If you remove the handle and look inside to find that the teeth grips are stripped, you may be able to find a replacement handle at your local hardware store. If the handle isn’t the problem you may have stripped gears on the crank itself. This isn’t too difficult to repair. The problem may be finding a replacement crank.
Once you inspect the crank mechanism and find that it is stripped you will have to remove it. The first thing you will need to do is to remove the crank arm from its guide track. Just remove the screen and open the window until the plastic guide bushings line up with the guide track notch. You should be able to slip the arm off from the window track.
You next look for the mounting screws inside the screen track. You will need to unscrew them so that you can remove the cover to be able to get to the cranks inside. If there aren’t any trim screws the casement cover may be nailed or stapled in place. You will need to slip a stiff putty knife between the casement cover and the window frame. You should be able to pry the casing off, just be careful not to damage the wood parts.
Take the old crank mechanism to the hardware store to see if they have a replacement you can get or if they don’t they may be able to send your old crank off to be matched by one of their suppliers. All you can do till the replacement part arrives is close and lock the window.
When the replacement part arrives you mount the crank box to the same place the old unit was, making sure the crank arm is reattached to the window. You may have to attach the crank handle once you have the box remounted. just slip the handle over the crank gear so that the teeth engage, then tighten the set screw. Open and close the window with the crank handle a couple times to make sure it operates smoothly. If it seems to hesitate you may need to remount the crank box to ensure proper alignment.
The hardest thing about trying to repair casement window cranks is being able to find the proper replacement crank. Most window manufactures don’t put their name on the window or casing. You may look into the sash of the window frame and may find the manufacture there. If you do you can contact them directly to see if they carry replacement crank parts. This will assure you of the best crank replacement. If you can’t find the name of the window manufacturer, your only choice is to see if a local home or hardware store can send off for a replacement crank.