To understand the espag handle it will help to firstly explain what an espag is. An espagnolette locking system (shortened to espag) is the flat metal strip which runs up the locking side of a window and moves when the handle is turned. Often they have round studs on them called mushrooms which move up and down (or side to side depending on how your window sits) when the handle is moved. The mushrooms then catch into a metal plate on the window frame called a keep. In the centre of the espag is a gearbox with a square hole in it and the spindle from the handle goes through this hole, when the handle is turned it operates the mechanism moving the mushrooms backwards and forwards.
So you can see why the handle which moves an espag mechanism is called an espag window handle.
Some parts of an espag handle have become standard throughout the double glazing industry – the fixing holes are always 43mm apart and the spindle is always 7mm wide. The length of the spindle will differ and can range from 10mm up to 40mm. Some companies, such as Anglian Windows, occasionally used longer spindles up to 60mm but these have been phased out generally.
Just to spoil the lovely descriptions the espag handle is also used to operate other types of window systems such as gearboxes and shootbolt systems. But the companies making these systems have stuck to the standards and so they are operated using espag window handles.
What is an Espag Handle?