Before you install your pivot locks check if your frame has steel reinforcement. This is done by drilling a pilot hole into the frame (3mm drill bit recommended). When drilling this hole you should feel tension from the steel meaning you can then drill straight into the frame with the screws we supply. If there is no tension and the frame is hollow inside, you will need to use Jack nuts for fitting. Jack Nuts with 5mm machine screw to suit are supplied separately. To install the Jack nuts you first need to drill an 8.5mm hole. Then insert the Jack nut it should be fairly tight. Then insert the machine screw and tighten until it expands fully behind the uPVC. There are specific tools for this product but if you take your time you shouldn’t have a problem. Make sure to use the correct Philips head screwdriver or pozi bit in order not to strip the screw heads.