Re: cutting a bridge?
Joey, Theodie showed me a great way to notch the saddles on a bridge. I am going to assume you are using a Gibson style ABR or Nashville.
Go ahead and string the guitar up on the un-notched saddles. Get yourself a rubber mallet, or if you don't have one a regular hammer will work, just be careful. Make sure the string is alligned on the saddle exactly where you want it, and give it a firm rap with the hammer. All you're looking to do is get a "slight" indentation in the saddle. Do this for each saddle (it will of course ruin the strings).
Take the strings off, and either using your file, or the correct string size for each saddle wrapped with some sandpaper, smooth the notch out so there are no burr's.
You're done. Really easy, works like a charm. Remember, you don't need a deep grove at all, because that can cause binding, string breakage, ect. Just a smooth little notch to hold the string in place.