In the last panel, of your tool, there will be a time where you need to change your blade. It is very important that you keep your tools and blades, in particular, very sharp. Usually, on every tool, you have a little key, that comes with the tool. In this particular case, it comes with a nice nifty storage space, in the handles. On the most, skilled saw, you will find a little locking pin that will prevent the blade from spinning, while you're undoing the shaft screw. You lock the pin in place; you place the key onto the locking screw and gently, undo it. You pull the guard back and your blade is ready to pop out but make sure the vibration collar does not get lost, it is very important. Once you replace the blade, you utilize the reverse procedure. You put the vibrating collar on, you screw the screw in, you press the locking level, on the back and you tighten it up. Make sure you do not over tighten and you're ready to go.