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Operators are a system of gears, cranks and arms that move a casement or awning window open or closed.

As the crank handle turns, an internal worm gear spins and moves a gear that moves the arms that attach to the casement or awning sash.


The sash has shoes attached to it that ride in metal tracks screwed to top and bottom of the window.  

Casement operators are specific to the side of the window it is located. They are named based on the view from the building's exterior when itemized or ordered: Left Hand From Outside or Right Hand From Outside.

Signs of a broken operator

  • Crank spins but the sash does not move

  • Crank is requires excessive force to operate

  • Operator arms are rusted

  • Casement can't shut normally

Why do operators break?

Operators break from lack of maintenance, problems with the window's opening and user error.

All moving parts need regular cleaning and lubrication to prevent corrosion. Casement and awning windows are especially prone to collecting debris like leaves, dirt, insect carcasses and nests because the design has a lot of openings and gaps for the hardware to function properly. 

Casements run into issues opening and closing when the window sill heaves or shifts, or if the sash was installed too tightly by the initial contractor. This causes the sash to rub on the sill leaving a distinct rub mark. This causes the window to need more force to operate and wears down the operator. Our Window Wellness Service © includes surface-level adjustment to the sill and shimming the sash as necessary to get the sash to clear the sill properly.

Casements windows usually have wood sills. If the sill is pitched in towards the house or has sitting water, the wood will rot. The first part to rot is usually the wood around the screws, causing the screws to back out. We can dowel the screw holes and offer solutions to prevent further water damage like toe beading and early rot repair.

Lastly, users will damage the operator by using excessive force when cranking it open or shut. When an operator is poorly maintained, it will become harder to crank. Operator cranks turn an internal worm gear that turns the cranks that move the arms attached to the sash. Some window users believe that the harder they crank, the better the seal. This is false, the seal comes from the weatherstripping and the locks. When closing your casement or awning window, stop cranking when the sash stops. Use the locks to finish closing the window. Excessive force breaks the worm gear and the whole operator needs to be replaced. If the locks cannot meet the keepers at this point, the window needs maintenance to open and close properly.

Types of Operators

There is a wide variety of models and manufacturers for operators. We have some standard models in stock and we can order the specific make and model operator for your window. Below you can learn about the basic design variations of operators.

Single Arm Casement Operator

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Dual Arm Casement Operator

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Awning Operator

Dual Arm Operator

Operator Icon edited.jpg

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