Face Fixed: When it comes to fixing your fly screens to the face of a window there are two methods;
Note: Turn buckles are sold as an add on to your fly screen order in a pack of four.
Recess Fixed: Angle your new screen into the frame, provided you have made the correct deductions you should be able to sit the right hand side of the frame into the inside of the recess with the left hand side able to clear the outside edge of the recess.
Your recess should be sufficient to contain the fly screen and allow removal, however in some cases it is not and to gain additional fixing you can use a springer.Springers are fitted to the screens at the time of manufacture, they are small aluminium sections with a spring attached to that allows the ends to be retracted for easy removal. They can be fitted to just one side of the screen or both sides of the screen depending on the type of window. They are very useful for internal winder and casement style windows. To locate them into timber simply tap the back of the springer to create a mark then with a 5 mm drill create a hole. If required this can also be done to aluminium.